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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. Nuclear quadrupole resonance echoes from hexamethylenetetramine.

    PubMed

    Ota, Go; Itozaki, Hideo

    2006-10-01

    We investigated the echo phenomenon of nuclear quadrupole resonance (NQR) from hexamethylenetetramine (HMT). We detected the pure NQR echo signal of HMT with a short pulse interval. The intensity of the echo signal increased as the pulse interval time was decreased. We observed that a clean echo signal was generated even when the pulse interval was shorter than the decay time constant T(2)(*). Since the short interval time gives a strong echo, our result insists that shorter interval time is preferred for the NQR detection.

  3. 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.

  4. Emission of nuclear quadrupole resonance from polycrystalline hexamethylenetetramine.

    PubMed

    Ota, G; Itozaki, H

    2008-03-01

    The angular dependence of the nuclear quadrupole resonance (NQR) signal intensity emitted from polycrystalline hexamethylenetetramine has been analytically investigated for all directions for non-contact detection of chemicals by nuclear quadrupole resonance. The field pattern of the NQR signal from a column sample was measured. The emitted patterns were the same as that from a united single magnetic dipole, which fitted well to the estimation based on quadrupole principle axis system. This result is helpful to design an antenna for NQR remote detection.

  5. Simulation of nuclear quadrupole resonance for sensor probe optimization.

    PubMed

    Shinohara, Junichiro; Sato-Akaba, Hideo; Itozaki, Hideo

    2012-01-01

    A simulation method to estimate the detection efficiency of nuclear quadrupole resonance (NQR) was proposed for optimizing a sensing probe operating at radio frequencies (RFs). It first calculates the transmitted magnetic field from the probe coil to the target sample. The nuclei make quadrupole resonance by it. We considered this nonlinear reaction to estimate NQR emission by the nuclei. Then the received NQR signal intensity from the sample at the probe coil. We calculated the efficiency by testing two different probe types (solenoid and gradiometer) and by changing the relative positions of the probe and sample. The simulation results were in good agreement with the experimental results.

  6. Nuclear quadrupole resonance detection of explosives: an overview

    NASA Astrophysics Data System (ADS)

    Miller, Joel B.

    2011-06-01

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

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

    SciTech Connect

    Chang, J.W.

    1991-07-01

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

  8. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Sensing of chemical substances using SQUID-based nuclear quadrupole resonance

    NASA Astrophysics Data System (ADS)

    Tachiki, M.; He, D. F.; Itozaki, H.

    2007-10-01

    Using a high-Tc radio frequency superconducting quantum interference device (rf SQUID) with a normal metal transformer, we successfully detected the nuclear quadrupole resonance (NQR) at about 888 kHz of 14N in p-nitrotoluene (PNT) at room temperature. Only one coil was used as the resonator coil for the transmission and the pickup coil of the transformer. To reduce the influence of the strong excitation field, cross diodes and switches were inserted in the transformer. The signal-to-noise ratio of the NQR spectrum using high-Tc rf SQUID system was comparable to that of using a low noise preamplifier.

  18. 14N nuclear quadrupole resonance of p-nitrotoluene using a high-Tc rf SQUID

    NASA Astrophysics Data System (ADS)

    He, D. F.; Tachiki, M.; Itozaki, H.

    2007-03-01

    Using a high-Tc radio-frequency superconducting quantum interference device (rf SQUID), we successfully detected nuclear quadrupole resonance (NQR) at about 887 kHz for 14N in p-nitrotoluene (PNT). A normal metal transformer made of copper wire was used to improve the sensitivity of the high-Tc rf SQUID and pulse-controlled rf switches and cross diodes were inserted in the transformer to reduce the influence of the strong excitation field. The preliminary results for NQR detection using the high-Tc SQUID had a similar signal-to-noise ratio to that of using a low noise preamplifier.

  19. Rabi and Larmor nuclear quadrupole double resonance of spin-1 nuclei

    NASA Astrophysics Data System (ADS)

    Prescott, D. W.; Malone, M. W.; Douglass, S. P.; Sauer, K. L.

    2012-12-01

    We demonstrate the creation of two novel double-resonance conditions between spin-1 and spin-1/2 nuclei in a crystalline solid. Using a magnetic field oscillating at the spin-1/2 Larmor frequency, the nuclear quadrupole resonance (NQR) frequency is matched to the Rabi or Rabi plus Larmor frequency, as opposed to the Larmor frequency as is conventionally done. We derive expressions for the cross-polarization rate for all three conditions in terms of the relevant secular dipolar Hamiltonian, and demonstrate with these expressions how to measure the strength of the heterogenous dipolar coupling using only low magnetic fields. In addition, the combination of different resonance conditions permits the measurement of the spin-1/2 angular momentum vector using spin-1 NQR, opening up an alternate modality for the monitoring of low-field nuclear magnetic resonance. We use ammonium nitrate to explore these resonance conditions, and furthermore use the oscillating field to increase the signal-to-noise ratio per time by a factor of 3.5 for NQR detection of this substance.

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

    SciTech Connect

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

    1998-06-01

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

  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. Atomic Magnetometer Multisensor Array for rf Interference Mitigation and Unshielded Detection of Nuclear Quadrupole Resonance

    NASA Astrophysics Data System (ADS)

    Cooper, Robert J.; Prescott, David W.; Matz, Peter; Sauer, Karen L.; Dural, Nezih; Romalis, Michael V.; Foley, Elizabeth L.; Kornack, Thomas W.; Monti, Mark; Okamitsu, Jeffrey

    2016-12-01

    An array of four 87Rb vector magnetometers is used to detect nuclear quadrupole resonance signals in an unshielded environment at 1 MHz. With a baseline of 25 cm, the length of the array, radio-frequency interference mitigation is also demonstrated; a radio-station signal is suppressed by a factor of 20 without degradation to the signal of interest. With these compact sensors, in which the probe beam passes through twice, the fundamental limit to detection sensitivity is found to be photon-shot noise. More passes of the probe beam overcome this limitation. With a sensor of similar effective volume, 0.25 cm3 , but 25 × more passes, the sensitivity is improved by an order of magnitude to 1.7 ±0.2 fT /√{Hz } .

  3. 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.

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

    PubMed

    Lavrič, Zoran; Pirnat, Janez; Lužnik, Janko; Puc, Uroš; Trontelj, Zvonko; Srčič, Stane

    2015-06-01

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

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

    DOE PAGES

    Koutroulakis, Georgios; Yasuoka, Hiroshi; Tobash, Paul H.; ...

    2016-10-10

    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 5f valence electrons. Here, we present a detailed 69,71Ga 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 andmore » 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. Lastly, these findings are discussed within the context of different theoretical proposals for the unconventional pairing mechanism in heavy-fermion superconductors.« less

  6. DC SQUID Spectrometers for Nuclear Quadrupole and Low-Field Nuclear Magnetic Resonance Spectroscopy

    SciTech Connect

    TonThat, Dinh M.

    1998-04-01

    The dc Superconducting Quantum Interference Device (SQUJD) is a very sensitive detector of magnetic flux, with a typical flux noise of the order of 1 μΦ0Hz-1/2 at liquid helium temperature (Φ0=h/2e). This inherent flux sensitivity of the SQUID is used in a spectrometer for the detection of nuclear magnetic resonance (NMR.)and nuclear quadruple resonance (NQR). The processing magnetic field from the nuclear spins is coupled to the SQUID by mean of a flux transformer. The SQUID NMR spectrometer is used to measure the longitudinal relaxation time T1 of solid 129Xe at 4.2 K down to 0.1 mT.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

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

    PubMed

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

    2002-07-01

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

  9. 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.

  10. 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.

  11. 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.

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

    SciTech Connect

    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.

  13. 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.

  14. Nuclear Quadrupole Resonance (NQR) Method and Probe for Generating RF Magnetic Fields in Different Directions to Distinguish NQR from Acoustic Ringing Induced in a Sample

    DTIC Science & Technology

    1997-08-01

    77,719 TITLE OF THE INVENTION NUCLEAR QUADRUPOLE RESONANCE ( NQR ) METHOD AND PROBE FOR GENERATING RF MAGNETIC FIELDS IN DIFFERENT DIRECTIONS TO...DISTINGUISH NQR FROM ACOUSTIC RINGING INDUCED IN A SAMPLE BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a...nuclear quadrupole 15 resonance ( NQR ) method and probe for generating RF magnetic fields in different directions towards a sample. More specifically

  15. Nuclear Quadrupole Resonance Investigation of Spin Dynamics in the Praseodymium Trihalides Praseodymium Trichloride and Praseodymium Tribromide.

    NASA Astrophysics Data System (ADS)

    Su, Sunyu

    The spin dynamics of PrCl_3 and PrBr_3 have been studied in the temperature range from 124mK to 297K using Nuclear Quadrupole Resonance (NQR) techniques. In the low temperature regime, the Pr ions are in the ground state, and the dynamical properties of PrX_3 (X = Cl,Br) are well described by a 1D XY model. The data have been shown to be in agreement with the predictions of a relaxation theory for a magnetic interaction based on a rigorous treatment of the longitudinal dynamical correlation function < S_sp{z}{m}(t)S_sp {z}{n}(t)> of the electronic pseudo-spins S^{m} associated with the crystalline electric field ground state. The fits to the data have yielded reasonable values for the hyperfine interaction parameters A and exchange integrals J/k_{B}. The dynamical properties of the PrX_3 compounds depart from the 1D model as the temperature increases. The spin lattice relaxation rates display unusual temperature dependences in the high temperature regime. These temperature dependences have been qualitatively accounted for by considering the effect of populating the excited states of the crystal electric field. The theory of NQR mixed spin echoes in solids has been established using the interaction representation formalism. The NQR mixed spin echoes theory has been applied to the study of the spin interactions in PrBr_3 . It has been shown that the second moments due to quadrupole interaction M_sp{2} {q}, magnetic dipole-dipole interactions between like spins M_sp{2}{II } and magnetic dipole-dipole interactions between unlike spins M_sp{2}{IS}(Br,Pr ^{3+}),M_sp{2}{IS }(^{79}Br,^{81}Br ) can be simultaneously determined. NQR spectra have been obtained for both praseodymium trihalides. The low temperature spectrum of PrCl _3 has provided strong support to the earlier results. In addition, the present investigation of the NQR spectrum has resulted in a better estimate of the magnitude of dimerization in PrCl_3. The PrBr_3 low temperature NQR spectrum has revealed

  16. 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.

  17. 53Cr, 17O and 14N nuclear quadrupole resonance in ammonium dichromate

    NASA Astrophysics Data System (ADS)

    Stephenson, David; Singh, Nadia

    2016-12-01

    The 53Cr resonance frequency in ammonium dichromate has been detected at 4202 kHz giving a Qcc of 8404 kHz (assuming η= 0). Calculations suggest that the value of the 53Cr quadrupole moment is about 84 mB lower that the currently accepted value. The resonance frequencies of two 17O nuclei have also been detected giving Qcc = 2800, 2890 kHz and η = 0.726, 0.780 respectively. The value for coupling and asymmetry parameter for 14N has been refined using zero field NQR giving a value Qcc = 78.8 kHz and η= 0.645 the asymmetry value being considerably lower than the value previous reported.

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

    SciTech Connect

    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 may be used 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. This material is based upon work supported by the U.S. Department of Energy Office of Science, Office of Basic Energy Sciences, Heavy Element Chemistry program.

  19. 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.

  20. Analysis of nuclear-quadrupole-resonance spectrum of incommensurate phases: The case of bis(4-chlorophenyl) sulfone

    NASA Astrophysics Data System (ADS)

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

    1998-02-01

    In this work, previous experimental studies of the 35Cl nuclear-quadrupole-resonance (NQR) line shape in the incommensurate phase of bis(4-chlorophenyl) sulfone were extended. The broad spectra in the incommensurate phase (IC) were measured using the Fourier transform of the nuclear signal to avoid systematic errors committed in some studies of this compound. The results were interpreted within the framework of the general treatment developed by Perez-Mato, Walisch, and Petersson. The effects of the incommensurate modulation on the asymmetry parameter of the electric-field gradient were explicitly included in the expression of the NQR frequency. The features of the spectra were adequately reproduced in the whole temperature range, by considering the nonsinusoidal character of the atomic modulations reported by x-ray diffraction. No evidences were found concerning IC wave fluctuations smearing out the singularities of the NQR spectrum. On the other hand, relative intensity of NQR peaks and temperature behavior of some parameters of the plane-wave ``local'' model were explicitly calculated. Comparison of these quantities with the experimental results excludes the applicability of the ``local'' model in the case of bis(4-chlorophenyl) sulfone.

  1. Peptide backbone orientation and dynamics in spider dragline silk and two-photon excitation in nuclear magnetic and quadrupole resonance

    NASA Astrophysics Data System (ADS)

    Eles, Philip Thomas

    2005-07-01

    In the first part of the dissertation, spider dragline silk is studied by solid state NMR techniques. The dependence of NMR frequency on molecular orientation is exploited using the DECODER experiment to determine the orientation of the protein backbone within the silk fibre. Practical experimental considerations require that the silk fibres be wound about a cylindrical axis perpendicular to the external magnetic field, complicating the reconstruction of the underlying orientation distribution and necess-itating the development of numerical techniques for this purpose. A two-component model of silk incorporating static b-sheets and polyglycine II helices adequately fits the NMR data and suggests that the b-sheets are well aligned along the silk axis (20 FWHM) while the helices are poorly aligned (68 FWHM). The effects of fibre strain, draw rate and hydration on orientation are measured. Measurements of the time-scale for peptide backbone motion indicate that when wet, a strain-dependent frac-tion of the poorly aligned component becomes mobile. This suggests a mechanism for the supercontraction of silk involving latent entropic springs that undergo a local strain-dependent phase transition, driving supercontraction. In the second part of this dissertation a novel method is developed for exciting NMR and nuclear quadrupole resonance (NQR) by rf irradiation at multiple frequencies that sum to (or differ by) the resonance frequency. This is fundamentally different than traditional NMR experiments where irradiation is applied on-resonance. With excitation outside the detection bandwidth, two-photon excitation allows for detection of free induction signals during excitation, completely eliminating receiver dead-time. A theoretical approach to describing two-photon excitation is developed based on average Hamiltonian theory. An intuition for two-photon excitation is gained by analogy to the coherent absorption of multiple photons requiring conservation of total energy and

  2. Nuclear Quadrupole Resonance Measurement of the Ferromagnetic Filled-Skutterudite Compound EuRu4Sb12

    NASA Astrophysics Data System (ADS)

    Koyama, Takehide; Maeda, Yoshitaka; Ueda, Koichi; Mito, Takeshi; Sugawara, Hitoshi

    2015-08-01

    We report the detailed analysis of the 101Ru nuclear quadrupolar resonance spectrum in the ferromagnetically ordered state of EuRu4Sb121 and propose that Eu 4f moments align in the [111] direction. The localized character of Eu 4f electrons is suggested from the temperature dependence of the nuclear spin-lattice relaxation rate.

  3. 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.

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

    PubMed Central

    2012-01-01

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

  5. 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.

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

    SciTech Connect

    Koutroulakis, Georgios; Yasuoka, Hiroshi; Tobash, Paul H.; Mitchell, Jeremy Neil; Bauer, Eric Dietzgen; Thompson, Joe David

    2016-10-10

    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 5f valence electrons. Here, we present a detailed 69,71Ga 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. Lastly, these findings are discussed within the context of different theoretical proposals for the unconventional pairing mechanism in heavy-fermion superconductors.

  7. Resonance methods in quadrupole ion traps

    NASA Astrophysics Data System (ADS)

    Snyder, Dalton T.; Peng, Wen-Ping; Cooks, R. Graham

    2017-01-01

    The quadrupole ion trap is widely used in the chemical physics community for making measurements on dynamical systems, both intramolecular (e.g. ion fragmentation reactions) and intermolecular (e.g. ion/molecule reactions). In this review, we discuss linear and nonlinear resonances in quadrupole ion traps, an understanding of which is critical for operation of these devices and interpretation of the data which they provide. The effect of quadrupole field nonlinearity is addressed, with important implications for promoting fragmentation and achieving unique methods of mass scanning. Methods that depend on ion resonances (i.e. matching an external perturbation with an ion's induced frequency of motion) are discussed, including ion isolation, ion activation, and ion ejection.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Nuclear electric quadrupole interactions in liquids entrapped in cavities

    NASA Astrophysics Data System (ADS)

    Furman, Gregory B.; Meerovich, Victor M.; Sokolovsky, Vladimir L.

    2016-12-01

    Liquids entrapped in cavities and containing quadrupole nuclei are considered. The interaction of the quadrupole moment of a nucleus with the electric field gradient is studied. In such a system, molecules are in both rotational and translational Brownian motions which are described by the diffusion equation. Solving this equation, we show that the intra- and intermolecular nuclear quadrupole interactions are averaged to zero in cavities with the size larger than several angstroms.

  13. Nuclear spin squeezing via electric quadrupole interaction

    NASA Astrophysics Data System (ADS)

    Aksu Korkmaz, Yaǧmur; Bulutay, Ceyhun

    2016-01-01

    Control over nuclear-spin fluctuations is essential for processes that rely on preserving the quantum state of an embedded system. For this purpose, squeezing is a viable alternative, so far that has not been properly exploited for the nuclear spins. Of particular relevance in solids is the electric quadrupole interaction (QI), which operates on nuclei having spin higher than 1/2. In its general form, QI involves an electric-field gradient (EFG) biaxiality term. Here, we show that as this EFG biaxiality increases, it enables continuous tuning of single-particle squeezing from the one-axis twisting to the two-axis countertwisting limits. A detailed analysis of QI squeezing is provided, exhibiting the intricate consequences of EFG biaxiality. The initial states over the Bloch sphere are mapped out to identify those favorable for fast initial squeezing, or for prolonged squeezings. Furthermore, the evolution of squeezing in the presence of a phase-damping channel and an external magnetic field are investigated. We observe that dephasing drives toward an antisqueezed terminal state, the degree of which increases with the spin angular momentum. Finally, QI squeezing in the limiting case of a two-dimensional EFG with a perpendicular magnetic field is discussed, which is of importance for two-dimensional materials, and the associated beat patterns in squeezing are revealed.

  14. A Report on the International Symposium on Nuclear Quadrupole Resonance Spectroscopy (5th) Held at the Laboratoire de Chimie du Coordination du CNRS, Toulouse, France, 10-14 September 1979,

    DTIC Science & Technology

    1980-09-03

    THIS PAGE (*Woun Da Entered __________________ RECAD INSTRUCTIOKSREPORT DOCUMENTATION PAGE BEFORS CORPLETUG PORN 1. REPORT NUMBER 2. GOVT ACCESSION NO...become a torrent . Second, the widespread vigor with which the problems of mathematical description of quadrupole resonance phe- nomena, especially

  15. Nuclear quadrupole interaction of highly polarized gas phase 131Xe with a glass surface

    NASA Astrophysics Data System (ADS)

    Butscher, R.; Wäckerle, G.; Mehring, M.

    1994-05-01

    We report nuclear magnetic resonance (NMR) experiments on 131Xe (I=3/2) gas-phase atoms which exhibit nuclear quadrupole interaction with the surface of the sample cell. Nuclear quadrupole coupling constants and quadrupole relaxation rates are obtained from the time-domain signal of the freely precessing nuclear magnetization in weak magnetic fields. The nuclear spin species is polarized by spin-exchange collisions with optically pumped ground-state spins of Rb gas atoms. The Rb atoms also present in the sample are used as a magnetometer to probe the free-induction decay of the nuclear-spin ensemble. The temperature dependence of both the effective quadrupole splittings and the relaxation rates are explained by a model for the surface interactions of a Xe atom adsorbed on the glass surface. The desorption is thermally activated with an activation energy of EA=0.12 eV. The surface diffusion of an adsorbed atom is characterized by an activation energy ED for thermally activated hopping between neighboring surface sites. Both energies enter the spectral density function governing wall-induced nuclear quadrupole relaxation. Our experimental results lead to the conclusion that they are on the same order of magnitude.

  16. A systematic investigation of hydrogen-bonding effects on the 17O, 14N, and 2H nuclear quadrupole resonance parameters of anhydrous and monohydrated cytosine crystalline structures: a density functional theory study.

    PubMed

    Mirzaei, Mahmoud; Elmi, Fatemeh; Hadipour, Nasser L

    2006-06-08

    A systematic computational study was carried out to characterize the 17O, 14N, and 2H nuclear quadrupole resonance (NQR) parameters in the anhydrous and monohydrated cytosine crystalline structures. To include the hydrogen-bonding effects in the calculations, the most probable interacting molecules with the central molecule in the crystalline phase were considered in the pentameric clusters of both structures. To calculate the parameters, couples of the methods B3LYP and B3PW91 and the basis sets 6-311++G** and CC-pVTZ were employed. The mentioned methods calculated reliable values of 17O, 14N, and 2H NQR tensors in the pentameric clusters, which are in good agreements with the experiment. The different influences of various hydrogen-bonding interactions types, N-H...N, N-H...O, and O-H...O, were observed on the 17O, 14N, and 2H NQR tensors. Lower values of quadrupole coupling constants and higher values of asymmetry parameters in the crystalline monohydrated cytosine indicate the presence of stronger hydrogen-bonding interactions in the monohydrated form rather than that of crystalline anhydrous cytosine.

  17. 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.

  18. Antiferromagnetic spin fluctuations and unconventional nodeless superconductivity in an iron-based new superconductor (Ca4Al2O(6-y))(Fe2As2): 75As nuclear quadrupole resonance study.

    PubMed

    Kinouchi, H; Mukuda, H; Yashima, M; Kitaoka, Y; Shirage, P M; Eisaki, H; Iyo, A

    2011-07-22

    We report 75As nuclear quadrupole resonance studies on (Ca4Al2O(6-y))(Fe2As2) with T(c) = 27  K. Measurement of nuclear-spin-relaxation rate 1/T1 has revealed a significant development of two-dimensional antiferromagnetic spin fluctuations down to T(c) in association with the smallest As-Fe-As bond angle. Below T(c), the temperature dependence of 1/T1 without any trace of the coherence peak is well accounted for by a nodeless s(±)-wave multiple-gaps model. From the fact that its T(c) is comparable to T(c) = 28  K in the optimally doped LaFeAsO(1-y) in which antiferromagnetic spin fluctuations are not dominant, we remark that antiferromagnetic spin fluctuations are not a unique factor for enhancing T(c) among Fe-based superconductors, but a condition for optimizing superconductivity should be addressed from the lattice structure point of view.

  19. Unconventional superconductivity and electron correlations in the cobalt oxyhydrate Na0.35CoO2.yH2O from nuclear quadrupole resonance.

    PubMed

    Fujimoto, Tatsuya; Zheng, Guo-qing; Kitaoka, Y; Meng, R L; Cmaidalka, J; Chu, C W

    2004-01-30

    We report a careful 59Co nuclear quadrupolar resonance measurement on the recently discovered cobalt oxyhydrate Na0.35CoO2.yH(2)O superconductor from T=40 K down to 0.2 K. We find that in the normal state the spin-lattice relaxation rate 1/T(1) follows a Curie-Weiss type temperature (T) variation, 1/T(1)T=C/(T-theta), with theta=-42 K, suggesting two-dimensional antiferromagnetic spin correlations. Below T(c)=3.9 K, 1/T(1) decreases with no coherence peak and follows a T(n) dependence with n approximately 2.2 down to approximately 2.0 K but crosses over to a 1/T(1) proportional to T variation below T=1.4 K, which suggests non-s-wave superconductivity. The data in the superconducting state are most consistent with the existence of line nodes in the gap function.

  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. 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.

  3. Identification of 20(S)-protopanaxatriol metabolites in rats by ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry and nuclear magnetic resonance spectroscopy.

    PubMed

    He, Chunyong; Zhou, Dandan; Li, Jia; Han, Han; Ji, Guang; Yang, Li; Wang, Zhengtao

    2014-01-01

    20(S)-Protopanaxatriol (PPT), one of the aglycones of ginsenosides, has been shown to exert cardioprotective effects against myocardial ischemic injury. However, studies on PPT metabolism have rarely been reported. This study is the first to investigate the in vivo metabolism of PPT following oral administration by ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-Q/TOF-MS) and nuclear magnetic resonance (NMR) spectroscopy. The structures of the metabolites were identified based on the characteristics of their MS data, MS(2) data, and chromatographic retention times. A total of 22 metabolites, including 17 phase I and 5 phase II metabolites, were found and tentatively identified by comparing their mass spectrometry profiles with those of PPT. Two new monooxygenation metabolites, (20S,24S)-epoxy-dammarane-3,6,12,25-tetraol and (20S,24R)-epoxy-dammarane-3,6,12,25-tetraol, were chemicallly synthesized and unambiguously characterized according to the NMR spectroscopic data. The metabolic pathways of PPT were proposed accordingly for the first time. Results revealed that oxidation of (1) double bonds at Δ((24,25)) to form 24,25-epoxides, followed by rearrangement to yield 20,24-oxide forms; and (2) vinyl-methyl at C-26/27 to form corresponding carboxylic acid were the predominant metabolic pathways. Phase II metabolic pathways were proven for the first time to consist of glucuronidation and cysteine conjugation. This study provides valuable and new information on the metabolism of PPT, which is indispensable for understanding the safety and efficacy of PPT, as well as its corresponding ginsenosides.

  4. Chlorine Nuclear Quadrupole Hyperfine Structure in the Vinyl - Chloride Complex

    NASA Astrophysics Data System (ADS)

    Leung, Helen O.; Marshall, Mark D.; Messinger, Joseph P.

    2015-06-01

    The microwave spectrum of the vinyl chloride--hydrogen chloride complex, presented at last year's symposium, is greatly complicated by the presence of two chlorine nuclei as well as an observed, but not fully explained tunneling motion. Indeed, although it was possible at that time to demonstrate conclusively that the complex is nonplanar, the chlorine nuclear quadrupole hyperfine splitting in the rotational spectrum resisted analysis. With higher resolution, Balle-Flygare Fourier transform microwave spectra, the hyperfine structure has been more fully resolved, but appears to be perturbed for some rotational transitions. It appears that knowledge of the quadrupole coupling constants will provide essential information regarding the structure of the complex, specifically the location of the hydrogen atom in HCl. Our progress towards obtaining values for these constants will be presented.

  5. Landmine Detection by Nuclear Quadrupole Resonance (NQR)

    DTIC Science & Technology

    2004-12-01

    14N nuclei present in the explosive (Hirshfeld and Klainer, 1980; Grechishkin, 1992; Rowe and Smith, 1996; Garroway et al., 2001; Deas et al., 2002...Mater. Chem., 7 (2), 229-235. Garroway , A.N., Buess, M.L., Miller, J.B., Suits, B.H., Hibbs, A.D., Barrall, G.A., Matthews, R. and Burnett, L.J

  6. 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.

  7. Nuclear electric quadrupole moment of potassium from the molecular method

    NASA Astrophysics Data System (ADS)

    Teodoro, Tiago Quevedo; Haiduke, Roberto Luiz Andrade; Visscher, Lucas

    2015-03-01

    The current standard nuclear quadrupole moments (NQMs) of the 39K , 40K , and 41K isotopes have recently been contested by Singh and co-workers on the basis of their atomic computational data [Singh et al., Phys. Rev. A 86, 032509 (2012), 10.1103/PhysRevA.86.032509]. Thus we performed relativistic calculations of electric field gradients at the potassium nuclei in three diatomic molecules (KF, KCl, and KBr) and combined these values with accurate experimental nuclear quadrupole coupling constants to provide an independent assessment of these NQMs. Our most accurate results, obtained by treating electron correlation with coupled cluster theory, employing a four-component Hamiltonian that includes the Gaunt two-electron correction, and with an incremented relativistic basis set of quadruple-ζ quality, yield Q (39K)=60.3 (6 ) , Q (40K)=-75.0 (8 ) , and Q (41K)=73.4 (7 ) mb . These values are in better agreement with the results obtained by Singh et al. and indicate that the standard NQMs should be revised.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Pulsed electron-nuclear-electron triple resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Thomann, Hans; Bernardo, Marcelino

    1990-05-01

    A new experimental technique, pulsed electron-nuclear-electron triple resonance spectroscopy, is demonstrated. It is based on a modification of the pulse sequence for electron-nuclear double resonance (ENDOR) in which two EPR and one NMR transition are irradiated. The irradiation of one EPR transition is detected via a second EPR transition. The nuclear hyperfine coupling, which separates these EPR transition frequencies, is the irradiated NMR transition. The major advantages of triple resonance spectroscopy include the ability to resolve overlapping nuclear resonances in the ENDOR spectrum and a more direct quantitative assignment of nuclear hyperfine and quadrupole couplings. The triple resonance experiment is an alternative to the recently proposed method of employing rapid magnetic field jumps between microwave pulses for generating hyperfine selective ENDOR spectra.

  14. 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.

  15. Relationship between magnetic fluctuations and superconductivity in Na x(H 3O) zCoO 2 · yH 2O revealed by a Co nuclear quadrupole resonance

    NASA Astrophysics Data System (ADS)

    Ishida, K.; Ihara, Y.; Takeya, H.; Michioka, C.; Yoshimura, K.; Takada, K.; Sasaki, T.; Sakurai, H.; Takayama-Muromachi, E.

    2007-09-01

    Nuclear quadrupole frequency (νQ) and spin-lattice relaxation rate 1/T1 of Co were measured on various bilayered hydrate (BLH) NaxCoO2 · yH2O (y ∼ 1.3) with different values of superconducting (SC) and magnetic-transition temperatures, Tc and TM, together with non-SC monolayered hydrate (MLH) NaxCoO2 · yH2O (y ∼ 0.7). In the temperature range above 70 K, 1/T1T in all samples follows the similar temperature dependence as each other. In the BLH compounds, 1/T1T is enhanced with decreasing temperature below 70 K, and the values of 1/T1T at Tc are larger in the higher-ν3 sample, where ν3 is the peak frequency of the NQR spectrum arising from ±5/2 ↔ ±7/2 transitions. The magnetic ordering is indicated from the prominent divergence of 1/T1T at TM and the presence of the internal field at the Co nuclear site in the samples with ν3 higher than 12.5 MHz. We analyze the temperature dependence of 1/T1T in all samples on the basis of identical formula, and discuss the relationship between magnetic fluctuations and superconductivity in the BLH cobaltate.

  16. 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.

  17. 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.

  18. Hyperfine and nuclear quadrupole coupling in chlorine and fluorine dioxides

    NASA Astrophysics Data System (ADS)

    Fernández, Berta; Christiansen, Ove; Jørgensen, Poul; Byberg, Jørgen; Gauss, Jürgen; Ruud, Kenneth

    1997-02-01

    The hyperfine and nuclear quadrupole coupling tensors have been calculated for the two chlorine dioxide isomers OClO and ClOO and for fluorine dioxide FOO. The coupled-cluster singles and doubles (CCSD) approach with a perturbative treatment of triple excitations [CCSD(T)] has been used and basis saturation has been investigated. For the symmetric isomer OClO close agreement is obtained with the accurate and detailed experimental data. For FOO a geometry optimization as well as a comparison of calculated and experimental hyperfine coupling tensors suggest a shorter F-O bond length than that obtained experimentally. For the isomer ClOO, calculations have been carried out at the theoretical equilibrium geometry determined by Peterson and Werner and at the geometry proposed by Byberg for the matrix isolated molecule. The hyperfine coupling tensors obtained at these two geometries are substantially different, but the estimated accuracy of the calculations is not high enough to allow a determination of the geometry of ClOO from the hyperfine data.

  19. Reconstruction of nuclear quadrupole interaction in (In,Ga)As/GaAs quantum dots observed by transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Sokolov, P. S.; Petrov, M. Yu.; Mehrtens, T.; Müller-Caspary, K.; Rosenauer, A.; Reuter, D.; Wieck, A. D.

    2016-01-01

    A microscopic study of the individual annealed (In,Ga)As/GaAs quantum dots is done by means of high-resolution transmission electron microscopy. The Cauchy-Green strain-tensor component distribution and the chemical composition of the (In,Ga)As alloy are extracted from the microscopy images. The image processing allows for the reconstruction of the strain-induced electric-field gradients at the individual atomic columns extracting thereby the magnitude and asymmetry parameter of the nuclear quadrupole interaction. Nuclear magnetic resonance absorption spectra are analyzed for parallel and transverse mutual orientations of the electric-field gradient and a static magnetic field.

  20. Introduction to nuclear magnetic resonance.

    PubMed

    Mlynárik, Vladimír

    2016-05-19

    Nuclear magnetic resonance spectroscopy is a useful tool for studying normal and pathological biochemical processes in tissues. In this review, the principles of nuclear magnetic resonance and methods of obtaining nuclear magnetic resonance spectra are briefly outlined. The origin of the most important spectroscopic parameters-chemical shifts, coupling constants, longitudinal and transverse relaxation times, and spectroscopic line intensities-is explained, and the role of these parameters in interpretation of spectra is addressed. Basic methodological concepts of localized spectroscopy and spectroscopic imaging for the study of tissue metabolism in vivo are also described.

  1. 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

  2. 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 C17O- and 13CO-labeled species.

    PubMed

    Park, K D; Guo, K M; Adebodun, F; Chiu, M L; Sligar, S G; Oldfield, E

    1991-03-05

    We have obtained the oxygen-17 nuclear magnetic resonance (NMR) spectra of a variety of C17O-labeled heme proteins, including sperm whale (Physeter catodon) myoglobin, two synthetic sperm whale myoglobin mutants (His E7----Val E7; His E7----Phe E7), adult human hemoglobin, rabbit (Oryctolagus cuniculus) hemoglobin, horseradish (Cochlearia armoracia) peroxidase (E.C. 1.11.1.7) isoenzymes A and C, and Caldariomyces fumago chloroperoxidase (E.C. 1.11.1.10), in some cases as a function of pH, and have determined their isotropic 17O NMR chemical shifts, delta i, and spin-lattice relaxation times, T1. We have also obtained similar results on a picket fence prophyrin, [5,10,15,20-tetrakis(alpha, alpha, alpha, alpha, alpha-pivalamidophenyl)porphyrinato]iron(II) (1-MeIm)CO, both in solution and in the solid state. Our results show an excellent correlation between the infrared C-O vibrational frequencies, v(C-O), and delta i, between v(C-O) and the 17O nuclear quadrupole coupling constant (e2qQ/h, derived from T1), and as expected between e2qQ/h and delta i. Taken together with the work of others on the 13C NMR of 13CO-labeled proteins, where we find an excellent correlation between delta i(13C) and v(Fe-C), our results suggest that 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 [Li, X.-Y., & Spiro, T.G. (1988) J. Am. Chem. Soc. 110, 6024]. The modulation of this interaction by the local charge field of the distal heme residue (histidine, glutamine, arginine, and possibly lysine) in a variety of species and mutants, as reflected in the NMR and IR measurements, is discussed, as is the effect of cysteine as the proximal heme ligand.

  3. The use of the pairing-quadrupole connections in PQM for application in nuclear systems

    NASA Astrophysics Data System (ADS)

    Drumev, K. P.; Georgieva, A. I.

    2016-03-01

    Within the algebraic realization of the Pairing-plus-Quadrupole Model /PQM/ in the framework of the Elliott's SU(3) Model,we present some particular applications for realistic nuclear systems. The probability distribution of the SU(3) basis states within the isovector, isoscalar and total pairing eigenstates is obtained through a numerical diagonalization of the PQM Hamiltonian in each limit. This allows the investigation of the interplay between the pairing and quadrupole interactions in the Hamiltonian of the PQM, containing all of them as limiting cases. The relative strengths of the dynamically symmetric quadrupole-quadrupole interaction with the considered types of pairing interactions are investigated systematically for systems like the 20Ne.

  4. Quadrupole splitting and isomer shifts in Te oxides investigated using nuclear forward scattering

    NASA Astrophysics Data System (ADS)

    Klobes, Benedikt; Barrier, Nicolas; Vertruyen, Benedicte; Martin, Christine; Hermann, Raphaël P.

    2014-04-01

    Nuclear forward scattering by 125Te is a viable alternative to conventional 125Te Mössbauer spectroscopy avoiding all source related issues. Using reference compounds with known hyperfine parameters and Te oxides exhibiting stereochemically active lone pairs, we show that nuclear forward scattering by 125Te can be reliably used to extract quadrupole splitting energy and relative isomer shift. The rough correlation between Te-Ocoordination and quadrupole splitting energy as put forward by Takeda and Greenwood (J. Chem. Soc. Dalton, 2207, 1975), is corroborated by the presented results.

  5. 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.

  6. Observation of nuclear quadrupole hyperfine structure in the infrared spectrum of hydrogen iodide using a tunable-diode laser

    NASA Technical Reports Server (NTRS)

    Strow, L. L.

    1980-01-01

    Nuclear quadrupole hyperfine structure has been observed in the 1-0 vibration-rotation band of hydrogen iodide with a tunable-diode laser. The measured splittings agree well with microwave measurements of the HI molecule. Evidence for a slight change in the iodine nuclear quadrupole coupling constant from the ground to first excited vibrational state in hydrogen iodide was found.

  7. a Measurement of the Isovector Giant Quadrupole Resonance in LEAD-208 Using Elastic Polarized Photon Scattering

    NASA Astrophysics Data System (ADS)

    Dale, Daniel Stanton

    This experiment used highly polarized tagged photons to measure polarization asymmetries for elastic scattering in ^{208}Pb in the energy region of the isovector giant quadrupole resonance (IVGQR). These measurements were performed at excitation energies between 16 and 30 MeV. Photons with enhanced linear polarization were obtained from an off-axis tagged photon beam by making a kinematic selection on the post-bremsstrahlung electrons. Scattered photons were detected in two large NaI(Tl) crystals. The polarization asymmetries clearly show the signature for interference between the isovector giant quadrupole resonance and the underlying electric dipole strength. The gross features of the IVGQR strength distribution were obtained in a relatively model independent manner. An isovector giant quadrupole resonance was observed at an excitation energy of 20.1 +/- 0.5 MeV, with a width of 6.3 +/- 0.5 MeV, and an energy weighted strength of 1.4 +/- 0.3 isovector sum rule units.

  8. 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.

  9. 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.

  10. N- Trichloro- and dichloroacetyl amino acids and compounds of amino acids with halogeno acetic acids: 35Cl nuclear quadrupole resonance spectroscopy; crystal structure of N- trichloroacetyl- glycine, - DL-alanine, and - L-alanine

    NASA Astrophysics Data System (ADS)

    Dou, Shi-qi; Kehrer, Armin; Ofial, Armin R.; Weiss, Alarich

    1995-02-01

    The crystal structures of N- trichloroacetyl- glycine ( N- TCA- G), N-trichloroacetyl-dl-alanine ( N-TCA- dl-A ), and N-trichloroacetyl- l-alanine ( N-TCA- l-A ) were determined. In addition, the 35Cl NQR spectra of these N-trichloroacetyl amino acids, of N-trichloroacetyl- l-valine ( N-TCA- l-V ), and of N- dichloroacetyl- glycine and - L-alanine were measured, mostly as a function of temperature. Compounds of glycine and L-alanine with chlorodifluoroacetic acid, of glycine and L-leucine with monochloroacetic acid, of glycine and L-leucine with dichloroacetic acid, and of glycine and L-leucine with trichloroacetic acid were also studied using 35Cl NQR. The structures (in picometres and degrees) were found to be as follows. N- TCA- G: Pna2 1, Z = 8, a = 1641, b = 1002, c = 1018. N-TCA- dl-A : {C2}/{c}, Z = 8, a = 3280, b = 556, c = 1031, β = 96.68. N-TCA- l-A: P1 , Z = 2, a = 967, b = 949, c = 619, α = 74.97, β = 74.20, γ = 61.20. The 35Cl NQR frequencies (ν) were observed in the range 35-41 MHz, and decrease with increasing temperature. Some of the resonances bleach out at a temperature ( Tb) far below the melting temperature; this provides information about the crystal structures at 77 K. No phase transitions were observed by differential thermal analysis between 77 and 295 K. The crystal structures are discussed in connection with the NQR results, and conclusions are drawn about the structures of the compounds for which only 35Cl NQR data are available.

  11. 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.

  12. Microcoil nuclear magnetic resonance spectroscopy.

    PubMed

    Webb, A G

    2005-08-10

    In comparison with most analytical chemistry techniques, nuclear magnetic resonance has an intrinsically low sensitivity, and many potential applications are therefore precluded by the limited available quantity of certain types of sample. In recent years, there has been a trend, both commercial and academic, towards miniaturization of the receiver coil in order to increase the mass sensitivity of NMR measurements. These small coils have also proved very useful in coupling NMR detection with commonly used microseparation techniques. A further development enabled by small detectors is parallel data acquisition from many samples simultaneously, made possible by incorporating multiple receiver coils into a single NMR probehead. This review article summarizes recent developments and applications of "microcoil" NMR spectroscopy.

  13. Ab initio Study of Nuclear Quadrupole Interactions in Selenium and Tellurium

    NASA Astrophysics Data System (ADS)

    Maharjan, N. B.; Paudyal, D. D.; Mishra, D. R.; Byahut, S. P.; Cho, Hwa-Suck; Scheicher, R. H.; Jeong, Junho; Das, T. P.

    2004-03-01

    We are systematically studying the influence of impurities in calcogenide glasses on the glass transition temperature using the first-principles Hartree-Fock cluster method. Results of our calculations on the electronic structures of pure selenium and tellurium chain systems, and with Te and Se impurities respectively, will be reported. By comparing the theoretically obtained nuclear quadrupole interaction (NQI) tensors for ^77Se and ^125Te with available experimental NQI tensors, we were able to test the accuracy of the calculated electronic structures. Good agreement for both the pure and the impurity systems has been found. We have also studied ^125Te NQI tensors in Te-Thiourea and compared our result with experimental data to check on the choice of the ^125Te quadrupole moment used.

  14. 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)

  15. 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.

  16. 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.

  17. 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.

  18. 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).

  19. 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.

  20. 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.

  1. A study of resonance electron capture ionization on a quadrupole tandem mass spectrometer.

    PubMed

    Wei, J; Liu, S; Fedoreyev, S A; Voinov, V G

    2000-01-01

    Procedures that allow the realization of resonance electron capture (REC) mode on a commercial triple-quadrupole mass spectrometer, after some simple modifications, are described. REC mass spectrometry (MS) and tandem mass spectrometry (MS/MS) experiments were performed and spectra for some compounds were recorded. In particular, the charge-remote fragmentation (CRF) spectra of [M - H](-) ions of docosanoic and docosenoic acids under low-energy collisionally activated dissociation (CAD) conditions were obtained, and showed that there were no significant differences for [M - H](-) ions produced at different resonances (i.e. for [M - H](-) ions with different structures). This observation was explained on the basis of results obtained from deuterium-labeled fatty acids, which showed that different CRF ions (but with the same m/z value in the absence of labels) could be produced by different mechanisms, and all of them were obviously realized under CAD conditions that made spectra practically indistinguishable. The other example, which compared the REC-MS/MS spectrum of [M - H](-) ions and EI-MS/MS spectrum of M(+.) ions of daidzein, demonstrated the potential of the REC-MS/MS technique for more complex structure elucidation.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. First-principles study of boron oxygen hole centers in crystals: Electronic structures and nuclear hyperfine and quadrupole parameters

    SciTech Connect

    Li Zucheng; Pan Yuanming

    2011-09-15

    The electronic structures, nuclear hyperfine coupling constants, and nuclear quadrupole parameters of fundamental boron oxygen hole centers (BOHCs) in zircon (ZrSiO{sub 4}, I4{sub 1}/amd) and calcite (CaCO{sub 3}, R3c) have been investigated using ab initio Hartree-Fock (HF) and various density functional theory (DFT) methods based on the supercell models with all-electron localized basis sets. Both exact HF exchange and appropriate correlation functionals are important in describing the BOHCs, and the parameter-free hybrid method based on Perdew, Burke, and Ernzerhof density functionals (PBE0) turns out to be the best DFT method in reproducing the electron paramagnetic resonance (EPR) data. Our results reveal three distinct types of simple-spin (S = 1/2) [BO{sub 3}]{sup 2-} centers in calcite: (i) the classic [BO{sub 3}]{sup 2-} radical with the D{sub 3h} symmetry and the unpaired spin equally distributed on the three oxygen atoms (i.e. the O{sub 3}{sup 5-} type); (ii) the previously reported [BO{sub 2}]{sup 0} center with the unpaired spin equally distributed on two of the three oxygen atoms (O{sub 2}{sup 3-}); and (iii) a new variety with {approx}90% of its unpaired spin localized on one (O{sup -}) of the three oxygen atoms with a long B-O bond (1.44 A). Calculations confirm the unusual [BO{sub 4}]{sup 0} center in zircon and show it to arise from a highly distorted configuration with 90% of the unpaired spin on one oxygen atom that has a considerably longer B-O bond (1.68 A) than its three counterparts (1.45 A). The calculated magnitudes and directions of {sup 11}B and {sup 17}O hyperfine coupling constants and nuclear quadrupole constants for the [BO{sub 4}]{sup 0} center in zircon are in excellent agreement with the 15 K EPR experimental data. These BOHCs are all characterized by a small negative spin density on the central B atom arising from spin polarization. Our calculations also demonstrate that the spin densities on BOHCs are affected substantially by

  7. Time-Reversal Symmetry Violation in Molecules Induced by Nuclear Magnetic Quadrupole Moments

    NASA Astrophysics Data System (ADS)

    Flambaum, V. V.; DeMille, D.; Kozlov, M. G.

    2014-09-01

    Recent measurements in paramagnetic molecules improved the limit on the electron electric dipole moment (EDM) by an order of magnitude. Time-reversal (T) and parity (P) symmetry violation in molecules may also come from their nuclei. We point out that nuclear T, P-odd effects are amplified in paramagnetic molecules containing deformed nuclei, where the primary effects arise from the T, P-odd nuclear magnetic quadrupole moment (MQM). We perform calculations of T, P-odd effects in the molecules TaN, ThO, ThF+, HfF+, YbF, HgF, and BaF induced by MQMs. We compare our results with those for the diamagnetic TlF molecule, where the T, P-odd effects are produced by the nuclear Schiff moment. We argue that measurements in molecules with MQMs may provide improved limits on the strength of T, P-odd nuclear forces, on the proton, neutron, and quark EDMs, on quark chromo-EDMs, and on the QCD θ term and CP-violating quark interactions.

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

    PubMed

    Fu, Li-juan; Vaara, Juha

    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: H2O, CH3NO2, CH3CH2OH, C6H6, C6H12 (cyclohexane), HI, XeF2, WF5Cl, and Pt(C2dtp)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(-3)-10(-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.

  9. 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.

  10. Nuclear Magnetic Resonance Technology for Medical Studies

    NASA Astrophysics Data System (ADS)

    Budinger, Thomas F.; Lauterbur, Paul C.

    1984-10-01

    Nuclear magnetic resonance proton imaging provides anatomical definition of normal and abnormal tissues with a contrast and detection sensitivity superior to those of x-ray computed tomography in the human head and pelvis and parts of the cardiovascular and musculoskeletal systems. Recent improvements in technology should lead to advances in diagnostic imaging of the breast and regions of the abdomen. Selected-region nuclear magnetic resonance spectroscopy of protons, carbon-13, and phosphorus-31 has developed into a basic science tool for in vivo studies on man and a unique tool for clinical diagnoses of metabolic disorders. At present, nuclear magnetic resonance is considered safe if access to the magnet environment is controlled. Technological advances employing field strengths over 2 teslas will require biophysical studies of heating and static field effects.

  11. 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.

  12. 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…

  13. 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)

  14. Off-resonance nutation nuclear magnetic resonance study of framework aluminosilicate glasses with Li, Na, K, Rb or Cs as charge-balancing cation.

    PubMed

    Dirken, P J; Nachtegaal, G H; Kentgens, A P

    1995-11-01

    Framework aluminosilicate glasses with varying charge-balancing cation (Li, Na, K, Rb and Cs) have been studied with 27Al and 29Si magic-angle spinning nuclear magnetic resonance (MAS NMR) and 27Al on-resonance and off-resonance nutation NMR spectroscopy. This first application of off-resonance nutation NMR to disordered samples proves that it is a promising technique for the determination of mean quadrupole interactions in amorphous systems. Linewidths for Al decrease systematically with increasing size of the cation, due to a decrease in the quadrupole interaction from 5.0 MHz for the Li glass to 2.8 MHz for the Cs glass. A simple point-charge model effectively predicts the decrease in the quadrupole interaction. This indicates that the alkali ion is located close to aluminum. Looking at the residual linewidth after subtraction of the quadrupole broadening, the Al chemical shift distribution does not change significantly with the type of alkali ion. The same is true for the observed Si linewidth.

  15. Microwave Spectrum, Structure, and Nuclear Quadrupole Coupling Constants of 1-Bromo-1-fluoroethane

    NASA Astrophysics Data System (ADS)

    Tatamitani, Yoshio; Kuwano, Susumu; Fuchigami, Kiyokatu; Oe, Sumio; Ogata, Teruhiko

    1999-08-01

    The microwave spectrum of 1-bromo-1-fluoroethane, CHBrF-CH3 and CHBrF-CH2D (79/81Br), has been studied for the first time from 8 to 41 GHz. A least-squares analysis of the observed a- and b-type transition frequencies gave rotational and centrifugal distortion constants and components of the bromine nuclear quadrupole coupling constant tensor in the principal axes system as follows: A = 8979.428(5) MHz, B = 2883.898(3) MHz, C = 2310.535(3) MHz, ΔJ = 0.74(2) kHz, ΔJK = 2.49(3) kHz, ΔK = 5.3(5) kHz, δJ = 0.146(1) kHz, δK = 2.75(4) kHz, χaa = 493.49(29) MHz, χbb - χcc = -38.89(11) MHz, and ‖χab‖ = 161.8(28) MHz for the CH79BrF-CH3 species; A = 8979.257(5) MHz, B = 2859.072(3) MHz, C = 2294.572(3), ΔJ = 0.76(2) kHz, ΔJK = 2.51(3) kHz, ΔK = 4.5(4) kHz, δJ = 0.145(1) kHz, δK = 2.70(4) kHz, χaa = 412.42(27) MHz, χbb - χcc = -32.56 (11) MHz, and ‖χab‖ = 133.3(3) MHz for the CH81BrF-CH3 species. The structural parameters are calculated from the 24 observed rotational constants, and electronic properties of the carbon-bromine bond in 1-bromo-1-fluoroethane are evaluated from the observed nuclear quadrupole coupling constants. These molecular properties are compared with those of other related molecules. The molecular structure of 1-bromo-1-fluoroethane is found to be very close to that of 1,1-difluoroethane except for the C-Br bond.

  16. Developing hyperpolarized krypton-83 for nuclear magnetic resonance spectroscopy and magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Cleveland, Zackary I.

    This dissertation discusses the production of highly nonequilibrium nuclear spin polarization, referred to as hyperpolarization or hp, in the nuclear spin I = 9/2 noble gas isotope krypton-83 using spin exchange optical pumping (SEOP). This nonequilibrium polarization yields nuclear magnetic resonance (NMR) signals that are enhanced three or more orders of magnitude above those of thermally polarized krypton and enables experiments that would otherwise be impossible. Krypton-83 possesses a nuclear electric quadrupole moment that dominates the longitudinal (T1) relaxation due to coupling of the quadrupole moment to fluctuating electric field gradients generated by distortions to the spherical symmetry of the electronic environment. Relaxation slows polarization buildup and limits the maximum signal intensity but makes krypton-83 a sensitive probe of its environment. The gas-phase krypton-83 longitudinal relaxation rate increases linearly with total gas density due to binary collisions. Density independent relaxation, caused by the formation of krypton-krypton van der Waals molecules and surface adsorption, also contributes to the observed rate. Buffer gases suppress van der Waals molecule mediated relaxation by breaking apart the weakly bound krypton dimers. Surface relaxation is gas composition independent and therefore more difficult to suppress. However, this relaxation mechanism makes hp krypton-83 sensitive to important surface properties including surface-to-volume ratio, surface chemistry, and surface temperature. The presence of surfaces with high krypton adsorption affinities (i.e. hydrophobic surfaces) accelerates the relaxation times and can produce T1 contrast in hp krypton-83 magnetic resonance imaging (MRI). Tobacco smoke deposited on surfaces generates strong T1 contrast allowing the observation of smoke deposition with spatial resolution. Conversely, water adsorption on surfaces significantly lengths the T1 times due competitive surface adsorption

  17. Electron Distributions in Hexagonal Selenium and Tellurium and Monoclinic Selenium with Dilute Impurities and Associated Nuclear Quadrupole Interactions*.

    NASA Astrophysics Data System (ADS)

    Maharjan, N. B.; Paudyal, D. D.; Mishra, D. R.; Byahut, S.; Aryal, M. M.; Cho, Hwa-Suck; Scheicher, R. H.; Chow, Lee; Jeong, Junho; Das, T. P.

    2006-03-01

    The electron structures of Selenium chains and rings with Te impurities in hexagonal and monoclinic structures respectively and Se impurities in Te chains in hexagonal lattice have been studied using Hartree-Fock cluster model including many-body effects, including lattice relaxation effects. The calculated electronic wave-functions are utilized to obtain ^77Se and ^125Te nuclear quadrupole coupling constants e^2qQ and asymmetry parameters η and compared with available experimental data from Mossbauer and perturbed angular correlation measurements. From our results, the expected nature of nuclear quadrupole interactions associated with Sb impurities will be discussed. *Supported by NSF US-Nepal Program and UGC Nepal **Also at UCF, Orlando

  18. First Measurement of the Giant Monopole and Quadrupole Resonances in a Short-Lived Nucleus: {sup 56}Ni

    SciTech Connect

    Monrozeau, C.; Khan, E.; Blumenfeld, Y.; Beaumel, D.; Ebran, J. P.; Frascaria, N.; Gupta, D.; Marechal, F.; Scarpaci, J-A.; Mittig, W.; Roussel-Chomaz, P.; Gelin, M.; Garg, U.; Gillibert, A.; Keeley, N.; Obertelli, A.

    2008-02-01

    The isoscalar giant monopole resonance (GMR) and giant quadrupole resonance (GQR) have been measured in the {sup 56}Ni unstable nucleus by inducing the {sup 56}Ni(d,d{sup '}) reaction at 50A MeV in the Maya active target at the GANIL facility. The GMR and GQR centroids are measured at 19.3{+-}0.5 MeV and 16.2{+-}0.5 MeV, respectively. The corresponding angular distributions are extracted from 3 deg. to 7 deg. A multipole decomposition analysis using distorted wave Born approximation with random phase approximation transition densities shows that both the GMR and the GQR exhaust a large fraction of the energy-weighted sum rule. The demonstration of this new method opens a broad range of giant resonance studies at intermediate-energy radioactive beam facilities.

  19. Nuclear quadrupole interaction of111Cd on type-1 Cu-sites in blue copper proteins

    NASA Astrophysics Data System (ADS)

    Tröger, W.; Butz, T.; Danielsen, E.; Bauer, R.; Thoenes, U.; Messerschmidt, A.; Huber, R.; Canters, G. W.; den Blaauwen, T.

    1993-03-01

    The nuclear quadrupole interaction (NQI) of111Cd substituted for Cu(II) on type-1 sites in blue copper proteins is characterized by high values of ω0 in the region of 300 Mrad/s, close to that for the catalytic zinc site in alcohol dehydrogenase. Type-1 Cu has usually two sulfur ligands and two nitrogen ligands and in some cases an oxygen ligand in either a distorted tetrahedral geometry or in a trigonal bipyramidal geometry. The near tetrahedral arrangement together with the ligand sphere containing the same number of sulfur ligands explains the value of ω0 in the blue copper proteins. The present work determined the partial NQI for methionine using the known structure of azurin. This value was then used in the angular overlap model to calculate the NQI for ascorbate oxidase the structure of which is also known and gave good agreement with experiment. NQI data for laccase and stellacyanin the structures of which are unknown, are also given.

  20. Nuclear quadrupole coupling constants for N2O: experiment and theory.

    PubMed

    Brown, Alex; Wasylishen, Roderick E

    2012-10-04

    The nuclear quadrupole coupling constants (NQCCs) for the nitrogen and oxygen nuclei in N(2)O have been determined using a variety of computational methods (MP2, QCISD, DFT with B3LYP, PBE0, and B3PW91 functionals, CCSD, CCSD(T), CASSCF, and MRCI) combined with correlation-consistent basis sets. When compared to the available experimental determinations, the results demonstrate that only CCSD(T) and MRCI methods are capable of accurately predicting the NQCCs of the central and terminal nitrogen atoms. The spin-rotation and magnetic shielding tensors have also been determined and compared to experimental measurements where available. (14)N and (17)O NMR relaxation data for N(2)O in the gas phase and a variety of solvents is reported. The increase in the ratio of (14)N spin-lattice relaxation times in solvent for the central and terminal nitrogens supports previous reports of the modification of the electric field gradients at these nuclei in van der Waals complexes. Ab initio computations for the linear FH···N(2)O complex confirm the large change in EFGs imposed by a single perturber.

  1. The temperature dependence of the nuclear quadrupole interaction of 44Ti(EC)44Sc in rutile

    NASA Astrophysics Data System (ADS)

    Butz, T.; Vianden, R.

    2013-05-01

    The temperature dependence of the Nuclear Quadrupole Interaction on 44Sc in rutile was measured by Time Differential Perturbed Angular Correlation in the temperature range from 300 K to 945 K. Whereas \\upomega _Q = eQV_zz/4hbar with Vzz denoting the largest component of the electric field gradient tensor in magnitude increases with increasing temperature, the asymmetry parameter η remains essentially constant. This observation fits into the systematic with other probes provided the sign of Vzz is negative.

  2. Enhanced effect of C P -violating nuclear magnetic quadrupole moment in a HfF+ molecule

    NASA Astrophysics Data System (ADS)

    Skripnikov, L. V.; Titov, A. V.; Flambaum, V. V.

    2017-02-01

    The HfF+ cation is a very promising system to use in the search for the electron electric dipole moment (EDM), and a corresponding experiment is carried out by JILA group [H. Loh, K. C. Cossel, M. C. Grau, K.-K. Ni, E. R. Meyer, J. L. Bohn, J. Ye, and E. A. Cornell, Science 342, 1220 (2013), 10.1126/science.1243683; K.-K. Ni, H. Loh, M. Grau, K. C. Cossel, J. Ye, and E. A. Cornell, J. Mol. Spectrosc. 300, 12 (2014), 10.1016/j.jms.2014.02.001. Here we theoretically investigate the cation to search for another effect which violates time-reversal (T ) and spatial parity (P ) symmetries—the nuclear magnetic quadrupole moment (MQM) interaction with electrons. We report an accurate ab initio relativistic electronic structure calculations of the molecular parameter WM=0.494 10/33Hz e cm2 that is required to interpret the experimental data in terms of the MQM of the Hf nucleus. For this we have implemented and applied the combined Dirac-Coulomb(-Gaunt) and relativistic effective core potential approaches to treat electron correlation effects from all of the electrons and to take into account high-order correlation effects using the coupled cluster method with single, double, triple and noniterative quadruple cluster amplitudes. We discuss interpretation of the MQM effect in terms of the strength constants of T ,P -odd nuclear forces, proton and neutron EDMs, the QCD parameter θ , and quark chromo-EDMs.

  3. Optically pumped nuclear magnetic resonance of semiconductors.

    PubMed

    Hayes, Sophia E; Mui, Stacy; Ramaswamy, Kannan

    2008-02-07

    Optically pumped NMR (OPNMR) of direct gap and indirect gap semiconductors has been an area of active research interest, motivated by both basic science and technological perspectives. Proposals to enhance and to spatially localize nuclear polarization have stimulated interest in this area. Recent progress in OPNMR has focused on exploring the experimental parameter space in order to elucidate details of the underlying photophysics of optical pumping phenomena. The focus of this review is on recent studies of bulk samples of GaAs and InP, namely, the photon energy dependence, the magnetic field dependence, and the phase dependence of OPNMR resonances. Models for the development of nuclear polarization are discussed.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Resonantly Detecting Axion-Mediated Forces with Nuclear Magnetic Resonance

    NASA Astrophysics Data System (ADS)

    Arvanitaki, Asimina; Geraci, Andrew A.

    2014-10-01

    We describe a method based on precision magnetometry that can extend the search for axion-mediated spin-dependent forces by several orders of magnitude. By combining techniques used in nuclear magnetic resonance and short-distance tests of gravity, our approach can substantially improve upon current experimental limits set by astrophysics, and probe deep into the theoretically interesting regime for the Peccei-Quinn (PQ) axion. Our method is sensitive to PQ axion decay constants between 109 and 1012 GeV or axion masses between 10-6 and 10-3 eV, independent of the cosmic axion abundance.

  9. 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.

  10. 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

  11. Nuclear collective motion with a coherent coupling interaction between quadrupole and octupole modes

    NASA Astrophysics Data System (ADS)

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

    2006-04-01

    A collective Hamiltonian for the rotation-vibration motion of nuclei is considered in which the axial quadrupole and octupole degrees of freedom are coupled through the centrifugal interaction. The potential of the system depends on the two deformation variables β2 and β3. The system is considered to oscillate between positive and negative β3 values by rounding an infinite potential core in the (β2,β3) plane with β2>0. By assuming a coherent contribution of the quadrupole and octupole oscillation modes in the collective motion, the energy spectrum is derived in an explicit analytic form, providing specific parity shift effects. On this basis several possible ways in the evolution of quadrupole-octupole collectivity are outlined. A particular application of the model to the energy levels and electric transition probabilities in alternating parity spectra of the nuclei Nd150, Sm152, Gd154, and Dy156 is presented.

  12. Optically detected nuclear magnetic resonance in n-GaAs using an on-chip microcoil

    NASA Astrophysics Data System (ADS)

    Chen, Y. S.; Huang, J.; Reuter, D.; Ludwig, A.; Wieck, A. D.; Bacher, G.

    2011-02-01

    Optically detected nuclear magnetic resonance (NMR) with micrometer resolution is demonstrated in n-GaAs using an on-chip microcoil. To trace the Overhauser field, the electron Larmor frequency is monitored via time-resolved magneto-optical Kerr rotation. Sweeping the frequency of the rf magnetic field induced by an on-chip microscale current loop, nuclear spin depolarization is achieved for each isotope species. The experimental data indicate an impact of a local quadrupole field, most likely caused by ionized donors, on the amplitude and linewidth of the NMR spectrum. By applying rf pulse sequences, the Rabi oscillation of A75s nuclear spins is obtained with an effective dephasing time of ˜200 μs.

  13. Nuclear magnetic resonance studies of lens transparency

    SciTech Connect

    Beaulieu, C.F.

    1989-01-01

    Transparency of normal lens cytoplasm and loss of transparency in cataract were studied by nuclear magnetic resonance (NMR) methods. Phosphorus ({sup 31}P) NMR spectroscopy was used to measure the {sup 31}P constituents and pH of calf lens cortical and nuclear homogenates and intact lenses as a function of time after lens enucleation and in opacification produced by calcium. Transparency was measured with laser spectroscopy. Despite complete loss of adenosine triphosphate (ATP) within 18 hrs of enucleation, the homogenates and lenses remained 100% transparent. Additions of calcium to ATP-depleted cortical homogenates produced opacification as well as concentration-dependent changes in inorganic phosphate, sugar phosphates, glycerol phosphorylcholine and pH. {sup 1}H relaxation measurements of lens water at 200 MHz proton Larmor frequency studied temperature-dependent phase separation of lens nuclear homogenates. Preliminary measurements of T{sub 1} and T{sub 2} with non-equilibrium temperature changes showed a change in the slope of the temperature dependence of T{sub 1} and T{sub 2} at the phase separation temperature. Subsequent studies with equilibrium temperature changes showed no effect of phase separation on T{sub 1} or T{sub 2}, consistent with the phase separation being a low-energy process. {sup 1}H nuclear magnetic relaxation dispersion (NMRD) studies (measurements of the magnetic field dependence of the water proton 1/T{sub 1} relaxation rates) were performed on (1) calf lens nuclear and cortical homogenates (2) chicken lens homogenates, (3) native and heat-denatured egg white and (4) pure proteins including bovine {gamma}-II crystallin bovine serum albumin (BSA) and myoglobin. The NMRD profiles of all samples exhibited decreases in 1/T{sub 1} with increasing magnetic field.

  14. 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.

  15. 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.

  16. 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.}

  17. Nuclear Magnetic Resonance Imaging. South Carolina Health Service Area 2

    SciTech Connect

    Not Available

    1984-12-01

    Contents include: Nuclear Magnetic Resonance Imaging (NMRI); (Clinical applications, Magnet types, Comparisons with other systems, Manpower, Manufacturers, Contraindications); Analysis of systems; (Availability, Accessibility, Cost, Quality, Continuity, Acceptability).

  18. Nonlinear optical processes at quadrupole polariton resonance in Cu2O as probed by a Z-scan technique

    NASA Astrophysics Data System (ADS)

    Mani, S.; Jang, J. I.; Ketterson, J. B.

    2010-09-01

    Employing a modified Z-scan technique at 2 K, we monitor not only the fundamental (ω) but also the frequency-doubled (2ω) and tripled (3ω) Z-scan responses in Cu2O when the input laser frequency ω is tuned to the two-photon quadrupole polariton resonance. The Z-scan response at ω allows us to accurately estimate the absolute number of polaritons generated via two-photon absorption. A striking dip is observed near the 2ω Z-scan focus which basically arises from Auger-type recombination of polaritons. Under high excitation levels, the 3ω Z-scan shows strong third harmonic generation. Based on the nonlinear optical parameters determined, we estimate the experimental polariton density achievable and propose a direction for polariton-based Bose-Einstein condensation in Cu2O .

  19. 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.

  20. Dynamic Nuclear Spin Resonance in n-GaAs

    NASA Astrophysics Data System (ADS)

    Chen, Y. S.; Reuter, D.; Wieck, A. D.; Bacher, G.

    2011-10-01

    The dynamics of optically detected nuclear magnetic resonance is studied in n-GaAs via time-resolved Kerr rotation using an on-chip microcoil for rf field generation. Both optically allowed and optically forbidden NMR are observed with a dynamics controlled by the interplay between dynamic nuclear polarization via hyperfine interaction with optically generated spin-polarized electrons and nuclear spin depolarization due to magnetic resonance absorption. Comparing the characteristic nuclear spin relaxation rate obtained in experiment with master equation simulations, the underlying nuclear spin depolarization mechanism for each resonance is extracted.

  1. 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.

  2. Rotational spectra, nuclear quadrupole hyperfine tensors, and conformational structures of the mustard gas simulent 2-chloroethyl ethyl sulfide

    NASA Astrophysics Data System (ADS)

    Tubergen, M. J.; Lesarri, A.; Suenram, R. D.; Samuels, A. C.; Jensen, J. O.; Ellzy, M. W.; Lochner, J. M.

    2005-10-01

    Rotational spectra have been recorded for both the 35Cl and 37Cl isotopic forms of two structural conformations of 2-chloroethyl ethyl sulfide (CEES). The rotational constants of the 35Cl and 37Cl isotopomers were used to identify the conformational isomers. A total of 236 hyperfine transitions have been assigned for 47 rotational transitions of the 35Cl isotope of a GGT conformer, and 146 hyperfine have been assigned for 37 rotational transitions of the 37Cl isotopomer. For the second conformer, a total of 128 (110) hyperfine and 30 (28) rotational transitions have also been assigned to the 35Cl ( 37Cl) isotopes of a TGT conformation. The extensive hyperfine splitting data, measured to high resolution with a compact Fourier transform microwave spectrometer, were used to determine both the diagonal and off-diagonal elements of the 35Cl and 37Cl nuclear quadrupole coupling tensors in the inertial tensor principal axis system. The experimental rotational constant data, as well as the 35Cl and 37Cl nuclear quadrupole coupling tensors, were compared to the results from 27 optimized ab initio (HF/6-311++G ∗∗ and MP2/6-311++G ∗∗) model structures.

  3. 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.

  4. Nuclear magnetic resonance imaging in medicine

    PubMed Central

    McKinstry, C S

    1986-01-01

    Using the technique of nuclear magnetic resonance (NMR, MR, MRI), the first images displaying pathology in humans were published in 1980.1 Since then, there has been a rapid extension in the use of the technique, with an estimated 225 machines in use in the USA at the end of 1985.2 Considerable enthusiasm has been expressed for this new imaging technique,3 although awareness of its high cost in the present economic climate has led to reservations being expressed in other quarters.2 The aim of this article is to give an outline of the present state of NMR, and indicate some possible future developments. ImagesFig 1Fig 2Fig 3(a)Fig 3 (b)Fig 4Fig 5Fig 6Fig 7 (a)Fig 7 (b)Fig 8Fig 9Fig 10 PMID:3811023

  5. 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.

  6. 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.

  7. Small-Volume Nuclear Magnetic Resonance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Fratila, Raluca M.; Velders, Aldrik H.

    2011-07-01

    Nuclear magnetic resonance (NMR) spectroscopy is one of the most information-rich analytical techniques available. However, it is also inherently insensitive, and this drawback precludes the application of NMR spectroscopy to mass- and volume-limited samples. We review a particular approach to increase the sensitivity of NMR experiments, namely the use of miniaturized coils. When the size of the coil is reduced, the sample volume can be brought down to the nanoliter range. We compare the main coil geometries (solenoidal, planar, and microslot/stripline) and discuss their applications to the analysis of mass-limited samples. We also provide an overview of the hyphenation of microcoil NMR spectroscopy to separation techniques and of the integration with lab-on-a-chip devices and microreactors.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. Nondestructive identification of isotopes using nuclear resonance fluorescence

    SciTech Connect

    Shizuma, Toshiyuki; Hayakawa, Takehito; Hajima, Ryoichi; Kikuzawa, Nobuhiro; Ohgaki, Hideaki; Toyokawa, Hiroyuki

    2012-01-15

    Nondestructive identification of heavy isotopes concealed in a thick iron box has been demonstrated by using nuclear resonance fluorescence. A quasi-monochromatic photon beam produced by the collision of laser quanta with high energy electrons was used for resonant excitation of nuclear levels in {sup 206}Pb and {sup 208}Pb. By measuring the resonant {gamma} rays emitted from {sup 206}Pb and {sup 208}Pb, each of these isotopes were clearly identified. The ratio of the effective thickness, i.e., concentration distribution, of these isotopes was deduced from the relative intensities of the measured nuclear resonance fluorescence strengths.

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

    SciTech Connect

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

    1988-08-01

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

  15. 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

  16. Structural analysis of strained quantum dots using nuclear magnetic resonance.

    PubMed

    Chekhovich, E A; Kavokin, K V; Puebla, J; Krysa, A B; Hopkinson, M; Andreev, A D; Sanchez, A M; Beanland, R; Skolnick, M S; Tartakovskii, A I

    2012-10-01

    Strained semiconductor nanostructures can be used to make single-photon sources, detectors and photovoltaic devices, and could potentially be used to create quantum logic devices. The development of such applications requires techniques capable of nanoscale structural analysis, but the microscopy methods typically used to analyse these materials are destructive. NMR techniques can provide non-invasive structural analysis, but have been restricted to strain-free semiconductor nanostructures because of the significant strain-induced quadrupole broadening of the NMR spectra. Here, we show that optically detected NMR spectroscopy can be used to analyse individual strained quantum dots. Our approach uses continuous-wave broadband radiofrequency excitation with a specially designed spectral pattern and can probe individual strained nanostructures containing only 1 × 10(5) quadrupole nuclear spins. With this technique, we are able to measure the strain distribution and chemical composition of quantum dots in the volume occupied by the single confined electron. The approach could also be used to address problems in quantum information processing such as the precise control of nuclear spins in the presence of strong quadrupole effects.

  17. Nuclear magnetic resonance parameters of atomic xenon dissolved in Gay-Berne model liquid crystal.

    PubMed

    Lintuvuori, Juho; Straka, Michal; Vaara, Juha

    2007-03-01

    We present constant-pressure Monte Carlo simulations of nuclear magnetic resonance (NMR) spectral parameters, nuclear magnetic shielding relative to the free atom as well as nuclear quadrupole coupling, for atomic xenon dissolved in a model thermotropic liquid crystal. The solvent is described by Gay-Berne (GB) molecules with parametrization kappa=4.4, kappa{'}=20.0 , and mu=nu=1 . The reduced pressure of P{*}=2.0 is used. Previous simulations of a pure GB system with this parametrization have shown that upon lowering the temperature, the model exhibits isotropic, nematic, smectic- A , and smectic- B /molecular crystal phases. We introduce spherical xenon solutes and adjust the energy and length scales of the GB-Xe interaction to those of the GB-GB interaction. This is done through first principles quantum chemical calculations carried out for a dimer of model mesogens as well as the mesogen-xenon complex. We preparametrize quantum chemically the Xe nuclear shielding and quadrupole coupling tensors when interacting with the model mesogen, and use the parametrization in a pairwise additive fashion in the analysis of the simulation. We present the temperature evolution of {129/131}Xe shielding and 131Xe quadrupole coupling in the different phases of the GB model. From the simulations, separate isotropic and anisotropic contributions to the experimentally available total shielding can be obtained. At the experimentally relevant concentration, the presence of the xenon atoms does not significantly affect the phase behavior as compared to the pure GB model. The simulations reproduce many of the characteristic experimental features of Xe NMR in real thermotropic LCs: Discontinuity in the value or trends of the shielding and quadrupole coupling at the nematic-isotropic and smectic-A-nematic phase transitions, nonlinear shift evolution in the nematic phase reflecting the behavior of the orientational order parameter, and decreasing shift in the smectic-A phase. The last

  18. Theory for ^77Se and ^125Te Nuclear Quadrupole Interactions in Selenium and Tellurium.

    NASA Astrophysics Data System (ADS)

    Suck-Cho, Hwa; Oh, Young-Kee; Park, Jin-Ho; Das, T. P.

    1998-03-01

    The electric field gradient(efg) tensors at ^77Se and ^125Te nuclei have been studied for the four systems involving each of these nuclei in both Selenium and Tellurium crystals utilizing the first principles Hartee-Fock Cluster procedure. Using the calculated efg for the pure systems and the experimental quadrupole coupling constants (e^2qQ), the quadrupole moments are determined to be Q(^77Se)=0.74±0,07(b) and Q(^125Te)=0.35±0.04(b). Comparison will be made with earlier values for the Q of the two nuclei. Using our values of Q and the calculated efg for ^77Se in tellurium and ^125Te in selenium, our values of e^2qQ agree within 15 per cent with that of experiment. The asymmetry parametrs η also agree reasonably well with experiment, but not as closely as the e^2qQ. Experimental results for η for ^125Te in selenium are needed to compare with theory.

  19. 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.

  20. 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)

  1. 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.

  2. Nuclear magnetic resonance data of C9H20OSi

    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'.

  3. Nuclear magnetic resonance data of C8H18OSi

    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'.

  4. Nuclear magnetic resonance data of C10H15

    NASA Astrophysics Data System (ADS)

    Kalinowski, H.-O.; Kumar, M.; Gupta, V.; Gupta, R.

    This document is part of Part 1 `Aliphatic 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'.

  5. Hyperfine selectivity using multiquantum electron-nuclear-electron triple resonance

    NASA Astrophysics Data System (ADS)

    Christidis, T. C.; Mchaourab, Hassane S.; Hyde, James S.

    1996-06-01

    Hyperfine selectivity is demonstrated in a continuous wave electron-nuclear double resonance (ENDOR) experiment. A multiquantum electron-electron double resonance (ELDOR) signal is monitored as a function of the nuclear radio frequency. The signs and relative intensities of the ENDOR lines permit separating the case where both ELDOR and ENDOR frequencies match hyperfine couplings from the cases where this condition is not satisfied.

  6. Accurate measurements of electric quadrupole hyperfine interactions of very dilute spins in magnetic solids

    NASA Astrophysics Data System (ADS)

    Chaplin, D. H.; Hutchison, W. D.; Prandolini, M. J.; Bowden, G. J.

    1998-01-01

    The application of double and triple resonance techniques to enhance signals in quadrupole interaction — nuclear magnetic resonance on oriented nuclei spectroscopy, is illustrated for the antiferromagnet ( 54Mn)MnBr 2-4H 2O. Unusual shifts of the quadrupolar split, higher order, ν ±2, ±1 subresonance, comparable to the NMRON linewidth, are observed and explained.

  7. Hartree-Fock-Cluster Investigation of Nuclear Quadrupole Interactions in Solid Chalcogens, Selenium and Tellurium.

    NASA Astrophysics Data System (ADS)

    Aryal, M. M.; Maharjan, N. B.; Paudyal, D. D.; Mishra, D. R.; Byahut, S. R.; Scheicher, R. H.; Badu, S. R.; Jeong, J.; Chow, Lee; Das, T. P.

    2008-03-01

    Using the first-principles Hartree-Fock Cluster Procedure, we have studied the electronic structures of pure chain like Selenium and Tellurium, pure ring structured Selenium, Tellurium impurity in chain and ring-structured Selenium and Selenium impurity in chain-structured Tellurium chain. For our investigations in all the systems we have carried out convergence studies with respect to variational basis set sizes,sizes of clusters and electron correlation effects using many-body perturbation theory. Using our calculated electronic field-gradient parameters q in the pure chain systems and employing the experimental quadrupole coupling constants (e^2qQ), the values Q(^77Se)=(0.50±0.04) 10-28 m^2 and Q(^125Te)=-(0.2±0.02) 10-28m^2. Results will also be presented for the asymmetry parameters η for the pure chain systems and the e^2qQ and η for ^77Se in selenium ring. Our calculated values for e^2qQ and η for the impurity systems will also be presented and compared with available experimental data and earlier theoretical results.

  8. 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.

  9. Nuclear magnetic resonance spectroscopy with single spin sensitivity

    PubMed Central

    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.

    2014-01-01

    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 29Si 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. PMID:25146503

  10. 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.

  11. Polywater: proton nuclear magnetic resonance spectrum.

    PubMed

    Page, T F; Jakobsen, R J; Lippincott, E R

    1970-01-02

    In the presence of water, the resonance of the strongly hydrogenbonded protons characteristic of polywater appears at 5 parts per million lower applied magnetic field than water. Polywater made by a new method confirms the infrared spectrum reported originally.

  12. Single Nuclear Spin Magnetic Resonance Force Microscopy

    DTIC Science & Technology

    2010-05-02

    Lab. In work not directly supported by this grant, these projects advanced MRFM detected Ferromagnetic Resonance ( FMR ) to enable studies of...directly supported by this grant, these projects advanced MRFM detected Ferromagnetic Resonance ( FMR ) to enable studies of submicron magnetic structures...our earlier NMR detection of 19F spins in CaF2 we have conducted 65Cu, 63Cu NMR stud- ies for studies of interface phenomena in multilayered magnetic

  13. Nuclear Magnetic Resonance and the BCS Theory

    NASA Astrophysics Data System (ADS)

    Slichter, Charles P.

    The author describes the inspiration for the experiment by Hebel and Slichter to measure the nuclear spin-lattice relaxation time in super-conductors, the design considerations for the experiment, the surprising experimental results, their theoretical treatment using the Bardeen-Cooper-Schrieffer theory, and how comparing the nuclear relaxation results with those for ultrasound absorption confirmed the central idea of the BCS theory, the BCS pair wave function.

  14. 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

    2016-04-07

    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.

  15. 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.

  16. Electron Paramagnetic Resonance and Electron-Nuclear Double Resonance Characterization of Point Defects in Titanium dioxide Crystals

    NASA Astrophysics Data System (ADS)

    Brant, Adam

    Electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) are used to characterize several point defects in titanium dioxide (TiO2) single crystals in the rutile phase. A defect reported in 1961 by P. F. Chester called the “A Center” is assigned to a neutral hydrogen donor. Many researchers believe that the model for this S = 1/2 defect is an interstitial titanium ion (Ti3+) and that Ti3+ interstitials are the most dominant shallow donor in TiO 2. I show that the model for the A center is a neutral hydrogen donor and suggest that the Ti3+ interstitial model is not the most prevalent shallow donor defect in TiO2. Substitutional Cu2+ defects that are unintentionally introduced to TiO2 (rutile) during growth are characterized and assigned to a Cu2+ ion with an adjacent oxygen vacancy. Exact matrix diagonalization is used here to compute accurate values for the nuclear quadrupole parameter. The reduced intensity of the Cu2+ EPR signal when the sample is illuminated with 442 nm laser light as well as the appearance of photoinduced EPR signals due to singly and doubly ionized oxygen vacancies provide evidence that the Cu2+ defect has an adjacent oxygen vacancy. Interstitial lithium ions (Li+) adjacent to Ti 3+ ions and substitutional Fe3+ defects (Fe 3+ - Li+) are also characterized. These defects were introduced to the rutile crystal by heating at 450 °C in LiOH powder for times on the order of several hours. Principal values and principal axis directions of the g matrix are calculated for the interstitial Li+ ion adjacent to a Ti3+ ion and photoinduced effects of the Fe 3+ - Li+ defect are examined.

  17. Nuclear magnetic resonance predictions for graphenes: concentric finite models and extrapolation to large systems.

    PubMed

    Vähäkangas, Jarkko; Ikäläinen, Suvi; Lantto, Perttu; Vaara, Juha

    2013-04-07

    Nuclear magnetic resonance (NMR) data for graphenes are mainly lacking in the literature. We provide quantitative first-principles quantum-chemical calculations of NMR chemical shifts and shielding anisotropies as well as spin-spin couplings and anisotropies for increasingly large, hexagon-like fragments of graphene, hydrogenated graphene (graphane) and fluorinated graphene (fluorographene). Due to the rapid convergence of finite molecular model results, the parameter values in the innermost region of large flakes of these materials approach the bulk limit. For nuclear shieldings in the finite band-gap graphane and fluorographene systems, as well as deuterium quadrupole couplings in graphane, these limiting values are verified by periodic gauge-including projector augmented wave (PAW) calculations at corresponding theoretical levels. The periodic PAW wave method was used for all systems to obtain periodic structures. A quantum-chemical cluster approach was used with novel completeness-optimised basis sets to calculate both the shielding and coupling tensors for planar carbon nanoflakes of increasing size. The geometry of the innermost part of the nanoflakes as well as the nuclear shieldings converge toward the periodic counterparts. The cluster method allows the calculation of the spin-spin coupling tensors of all the graphenes and--in contrast to the periodic approach--all the NMR properties for the zero-band-gap graphene itself. The obtained parameters provide a plausible starting point for experimental NMR investigations of graphenes.

  18. A triple resonance hyperfine sublevel correlation experiment for assignment of electron-nuclear double resonance lines

    NASA Astrophysics Data System (ADS)

    Potapov, Alexey; Epel, Boris; Goldfarb, Daniella

    2008-02-01

    A new, triple resonance, pulse electron paramagnetic resonance (EPR) sequence is described. It provides spin links between forbidden electron spin transitions (ΔMS=±1, ΔMI≠0) and allowed nuclear spin transitions (ΔMI=±1), thus, facilitating the assignment of nuclear frequencies to their respective electron spin manifolds and paramagnetic centers. It also yields the relative signs of the hyperfine couplings of the different nuclei. The technique is based on the combination of electron-nuclear double resonance (ENDOR) and electron-electron double resonance (ELDOR)-detected NMR experiments in a way similar to the TRIPLE experiment. The feasibility and the information content of the method are demonstrated first on a single crystal of Cu-doped L-histidine and then on a frozen solution of a Cu-histidine complex.

  19. 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.

  20. Nuclear magnetic resonance study of potassium dihydrophosphate

    NASA Astrophysics Data System (ADS)

    Uskova, N. I.; Podorozhkin, D. Yu.; Charnaya, E. V.; Nefedov, D. Yu.; Baryshnikov, S. V.; Bugaev, A. S.; Lee, M. K.; Chang, L. J.

    2016-04-01

    A powder sample of potassium dihydrophosphate KH2PO4 has been studied by the 31P NMR method in a wide temperature range covering the ferroelectric phase transition. Changes in the position and shape of the resonance line at the transition to the ferroelectric phase have been revealed. The parameters of the chemical shift tensor of 31P (isotropic shift, anisotropy, and asymmetry) in the ferroelectric phase have been calculated from the experimental data. A sharp increase in the anisotropy of the tensor at the phase transition has been demonstrated. Dielectric measurements have also been carried out to verify the transition temperature.

  1. 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…

  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. 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)

  4. 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.

  5. Quantum computing using electron-nuclear double resonances

    NASA Astrophysics Data System (ADS)

    Bowden, Charles M.; Dowling, Jonathan P.; Hotaling, Steven P.

    1997-07-01

    We consider the use of Electron-Nuclear Double Resonance (ENDOR) techniques in quantum computing. ENDOR resolution as a possible limiting factor is discussed. It is found that ENDOR and double-ENDOR techniques have sufficient resolution for quantum computing applications.

  6. 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.

  7. 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).…

  8. 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.

  9. 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.

  10. 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.

  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. 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.

  13. 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.

  14. Probing resonances in the Dirac equation with quadrupole-deformed potentials with the complex momentum representation method

    NASA Astrophysics Data System (ADS)

    Fang, Zhi; Shi, Min; Guo, Jian-You; Niu, Zhong-Ming; Liang, Haozhao; Zhang, Shi-Sheng

    2017-02-01

    Resonances play critical roles in the formation of many physical phenomena, and many techniques have been developed for the exploration of resonances. In a recent letter [Phys. Rev. Lett. 117, 062502 (2016), 10.1103/PhysRevLett.117.062502], we proposed a new method for probing single-particle resonances by solving the Dirac equation in complex momentum representation for spherical nuclei. Here, we develop the theoretical formalism of this method for deformed nuclei. We elaborate numerical details and calculate the bound and resonant states in 37Mg. The results are compared with those from the coordinate representation calculations with a satisfactory agreement. In particular, the present method can expose clearly the resonant states in a complex momentum plane and determine precisely the resonance parameters for not only narrow resonances but also broad resonances that were difficult to obtain before.

  15. {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.

  16. Non-Abelian effects in a quadrupole system rotating around two axes

    SciTech Connect

    Zwanziger, J.W.; Koenig, M.; Pines, A. Department of Chemistry, University of California, Berkeley, CA )

    1990-09-01

    The {sup 35}Cl nuclear quadrupole resonance spectrum of a single crystal of sodium chlorate (R. Tycko, Phys. Rev. Lett. 58, 2281 (1987)) rotating about two axes reflects a non-Abelian gauge potential. This gauge potential is an example of Wilczek and Zee's (Phys. Rev. Lett. 52, 2111 (1984)) generalization of Berry's phase to the adiabatic transport of degenerate states.

  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. 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.

  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. 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)].

  1. Nuclear Magnetic Resonance Evidence using D2O for Structured Water in Muscle and Brain

    PubMed Central

    Cope, Freeman W.

    1969-01-01

    The electric quadrupole moment of the deuterium nucleus provides a nuclear magnetic resonance (NMR) probe of electric field gradients, and thereby of organization of tissue water. 8-17% of H2O in rat muscle and brain was replaced by D2O from 50% deuterated drinking water. The peak height of the steady-state NMR spectrum of D in muscle water was 74% lower than that of an equal concentration of D2O in liquid water. Longitudinal NMR relaxation times (T1) of D in water of muscle and brain averaged 0.092 and 0.131 sec, respectively, compared with 0.47 sec in D2O in liquid water. Transverse NMR relaxation times (T2) averaged 0.009 and 0.022 sec in D2O of muscle and brain, respectively, compared with 0.45 sec in D2O in liquid water. These differences cannot be explained by paramagnetic ions or by magnetic inhomogeneities, which leaves increased organization of tissue water as the only tenable hypothesis. Evidence was also obtained that 27% of muscle water and 13% of brain water exist as a separate fraction with T2 of D2O less than 2 × 10-3 sec, which implies an even higher degree of structure. Each of the two fractions may consist of multiple subfractions of differing structure. PMID:5780710

  2. Single crystal nuclear magnetic resonance in spinning powders.

    PubMed

    Pell, Andrew J; Pintacuda, Guido; Emsley, Lyndon

    2011-10-14

    We present a method for selectively exciting nuclear magnetic resonances (NMRs) from well-defined subsets of crystallites from a powdered sample under magic angle spinning. Magic angle spinning induces a time dependence in the anisotropic interactions, which results in a time variation of the resonance frequencies which is different for different crystallite orientations. The proposed method exploits this by applying selective pulses, which we refer to as XS (for crystallite-selective) pulses, that follow the resonance frequencies of nuclear species within particular crystallites, resulting in the induced flip angle being orientation dependent. By selecting the radiofrequency field to deliver a 180° pulse for the target orientation and employing a train of such pulses combined with cogwheel phase cycling, we obtain a high degree of orientational selectivity with the resulting spectrum containing only contributions from orientations close to the target. Typically, this leads to the selection of between 0.1% and 10% of the crystallites, and in extreme cases to the excitation of a single orientation resulting in single crystal spectra of spinning powders. Two formulations of this method are described and demonstrated with experimental examples on [1-(13)C]-alanine and the paramagnetic compound Sm(2)Sn(2)O(7).

  3. Single crystal nuclear magnetic resonance in spinning powders

    NASA Astrophysics Data System (ADS)

    Pell, Andrew J.; Pintacuda, Guido; Emsley, Lyndon

    2011-10-01

    We present a method for selectively exciting nuclear magnetic resonances (NMRs) from well-defined subsets of crystallites from a powdered sample under magic angle spinning. Magic angle spinning induces a time dependence in the anisotropic interactions, which results in a time variation of the resonance frequencies which is different for different crystallite orientations. The proposed method exploits this by applying selective pulses, which we refer to as XS (for crystallite-selective) pulses, that follow the resonance frequencies of nuclear species within particular crystallites, resulting in the induced flip angle being orientation dependent. By selecting the radiofrequency field to deliver a 180 ○ pulse for the target orientation and employing a train of such pulses combined with cogwheel phase cycling, we obtain a high degree of orientational selectivity with the resulting spectrum containing only contributions from orientations close to the target. Typically, this leads to the selection of between 0.1% and 10% of the crystallites, and in extreme cases to the excitation of a single orientation resulting in single crystal spectra of spinning powders. Two formulations of this method are described and demonstrated with experimental examples on [1 - 13C]-alanine and the paramagnetic compound Sm2Sn2O7.

  4. 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%.

  5. 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.

  6. 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.

  7. 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.

  8. Nuclear magnetic resonance: principles of blood flow imaging

    SciTech Connect

    Mills, C.M.; Brant-Zawadzki, M.; Crooks, L.E.; Kaufman, L.; Sheldon, P.; Norman, D.; Bank, W.; Newton, T.H.

    1984-01-01

    Nuclear magnetic resonance (NMR) imaging with spin-echo techniques defines vascular structures with superb anatomic detail. Contrast agents are not necessary as there is intrinsic contrast between flowing blood and the vascular wall. The signal intensity from blood within the vessel lumen varies with the sequence of gradient and radiofrequency pulses used to generate the image as well as with the velocity of blood flow. Appropriate imaging techniques can optimize anatomic detail, distinguish slow from rapidly flowing blood, and serve to identify marked impairment or complete obstruction of flow in an artery or vein. Some examples of these principles in the intracranial circulation are illustrated.

  9. 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

  10. 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.

  11. 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.

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

    PubMed

    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 systems.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Bonner Prize Talk: Parity Violation in Compound-Nuclear Resonances

    NASA Astrophysics Data System (ADS)

    Bowman, J. David

    2002-04-01

    I will describe a series of experiments that observed large parity-violating asymmetries in the scattering of polarized neutrons from a number of nuclei. I will review statistical models of compound-nuclear resonances and the statistical interpretation of observables. I will present the results of the experiments and the analysis of the measured asymmetries to extract the strength function of the nuclear weak interaction. In A=232 10 of 10 measured asymmetries had a common sign, in contradiction to the predictions of statistical models. I will describe the interpretation of this phenomenon in terms of doorway states. I will summarize the status of theoretical efforts to obtain constraints on the couplings of the hadronic weak interaction from measured weak strength functions.

  19. Pairwise additivity in the nuclear magnetic resonance interactions of atomic xenon.

    PubMed

    Hanni, Matti; Lantto, Perttu; Vaara, Juha

    2009-04-14

    Nuclear magnetic resonance (NMR) of atomic (129/131)Xe is used as a versatile probe of the structure and dynamics of various host materials, due to the sensitivity of the Xe NMR parameters to intermolecular interactions. The principles governing this sensitivity can be investigated using the prototypic system of interacting Xe atoms. In the pairwise additive approximation (PAA), the binary NMR chemical shift, nuclear quadrupole coupling (NQC), and spin-rotation (SR) curves for the xenon dimer are utilized for fast and efficient evaluation of the corresponding NMR tensors in small xenon clusters Xe(n) (n = 2-12). If accurate, the preparametrized PAA enables the analysis of the NMR properties of xenon clusters, condensed xenon phases, and xenon gas without having to resort to electronic structure calculations of instantaneous configurations for n > 2. The binary parameters for Xe(2) at different internuclear distances were obtained at the nonrelativistic Hartree-Fock level of theory. Quantum-chemical (QC) calculations at the corresponding level were used to obtain the NMR parameters of the Xe(n) (n = 2-12) clusters at the equilibrium geometries. Comparison of PAA and QC data indicates that the direct use of the binary property curves of Xe(2) can be expected to be well-suited for the analysis of Xe NMR in the gaseous phase dominated by binary collisions. For use in condensed phases where many-body effects should be considered, effective binary property functions were fitted using the principal components of QC tensors from Xe(n) clusters. Particularly, the chemical shift in Xe(n) is strikingly well-described by the effective PAA. The coordination number Z of the Xe site is found to be the most important factor determining the chemical shift, with the largest shifts being found for high-symmetry sites with the largest Z. This is rationalized in terms of the density of virtual electronic states available for response to magnetic perturbations.

  20. Probing quantum confinement at the atomic scale with optically detected nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Kempf, James G.

    2001-09-01

    Near-band-gap circularly polarized excitation in III-V semiconductors provides spin-polarized electrons that transfer spin order to lattice nuclei via fluctuations in the contact hyperfine interaction. This process of optical nuclear polarization and the complementary technique of optical detection of nuclear magnetic resonance (NMR) provide extreme sensitivity enhancement and spatial selectivity in structured samples, enabling collection of NMR spectra from samples such as single quantum wells or dots containing as few as ˜105 nuclei. Combining these advances with novel techniques for high spectral resolution, we have probed quantum-confined electronic states near the interface of a single epitaxially grown Al1-x As/GaAs (x = 0.36) heterojunction. Using a novel strategy that we refer to as POWER (p&barbelow;erturbations o&barbelow;bserved w&barbelow;ith e&barbelow;nhanced ṟesolution) NMR, multiple-pulse time suspension is synchronized with bandgap optical irradiation to reveal spectra of effective spin Hamiltonians that are differences between those of the occupied and unoccupied photoexcited electronic state. The underlying NMR linewidth is reduced by three orders of magnitude in these experiments, enabling resolution of an asymmetric line shape due to light-induced hyperfine interactions. The results are successfully fit with the coherent nuclear spin evolution and relaxation theoretically expected for sites distributed over the volume of an electronic excitation weakly localized at a point defect. This analysis establishes a one-to-one relationship, which can be used to follow nuclear spin diffusion, between optical Knight shift and the radial position of lattice nuclei. We have also introduced POWER NMR techniques to characterize the change in electric field associated with cycling from light-on to light-off states via a linear quadrupole Stark effect (LQSE) of the nuclear spins. Simulations of these NMR spectra in terms of the radial electric fields of

  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. 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.

  3. Nuclear Fusion Rate Study of a Muonic Molecule via Nuclear Threshold Resonances

    NASA Astrophysics Data System (ADS)

    Faghihi, F.; Eskandari, M. R.

    This work follows our previous calculations of the ground state binding energy, size, and the effective nuclear charge of the muonic T3 molecule, using the Born-Oppenheimer adiabatic approximation. In our past articles, we showed that the system possesses two minimum positions, the first one at the muonic distance and the second at the atomic distance. Also, the symmetric planner vibrational model assumed between the two minima and the approximated potential were calculated. Following from the previous studies, we now calculate the fusion rate of the T3 muonic molecule according to the overlap integral of the resonance nuclear compound nucleus and the molecular wave functions.

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

    NASA Astrophysics Data System (ADS)

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

    2000-07-01

    Several demonstrations of resonance phenomena associated with nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) are described. The demonstrations comprise common orienteering compasses, whose needles represent magnetic dipoles, along with three collinear permanent magnets and a magnetic stir plate or pulseable electromagnets. The trio of permanent magnets provides a laterally uniform magnetic field, whose strength decreases with distance from the magnets. Resonance can be observed by adjusting the frequency of the magnetic stirrer to match the resonant frequency of the compass needle, which is shown to depend on magnetic field strength, that is, the needle's position relative to the permanent magnets. Another demonstration involves pulsing electromagnets that apply a perpendicular magnetic field that causes the compass needles to oscillate. The effects of shielding, spin-spin coupling, magnetogyric ratio, and free induction decay can also be demonstrated. By moving the trio of permanent magnets relative to the compasses, the MRI experiment can be mimicked. Complete instructions for the construction of the demonstrations, which can be used on an overhead projector, are included.

  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. 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.

  7. 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)

  8. Unconventional nuclear magnetic resonance techniques using nanostructured diamond surfaces

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  9. Giant resonances: Progress, new directions, new challenges

    SciTech Connect

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

    1989-01-01

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

  10. Nuclear Magnetic Resonance Studies in Heavy Fermion Materials

    NASA Astrophysics Data System (ADS)

    Shirer, Kent Robert

    29Si, 31P, and 115In nuclear magnetic resonance studies of heavy fermion materials URu2Si 2, CeRhIn5, and URu2Si2- xPx were conducted as a function of temperature, pressure, and, in the case of URu2Si2- xPx, doping. Knight shift measurements in these systems probe the hybridization between conduction and local f-electrons which is described by the heavy fermion coherence temperature, T*, and can be captured by a two fluid model. This model takes the dual nature of the local moments and the heavy electron fluid into account. In URu2Si2 in a pressure range from 0-9.1 kbar, spin-lattice-relaxation data were taken and suggest a partial suppression of the density of states below 30 K. The data are analyzed in terms of a two component spin-fermion model. The spin-lattice-relaxation behavior is then compared to other materials that demonstrate precursor fluctuations in a pseudogap regime above a ground state with long-range order. Nuclear magnetic resonance data in CeRhIn5 for both the In(1) and In(2) sites are also taken under hydrostatic pressure. The Knight shift data reveal a suppression of the hyperfine coupling to the In(1) site as a function of pressure, and the electric field gradient at the In(2) site exhibits a change of slope. These changes to these coupling constants reflect alterations to the electronic structure at the quantum critical point. Finally, we report 31P nuclear magnetic resonance measurements in single crystals of URu2Si2-xP x with x = 0.09, 0.33. In the case of the x = 0.09 doping, we find no evidence for a phase transition, though the material still exhibits heavy fermion coherence. In the x = 0.33 doping, we find that it undergoes an antiferromagnetic (AFM) phase transition. When we include the pure compound in our analysis, we find that the hyperfine couplings and coherence temperatures evolve with doping. We compare this evolution with the trends seen in other compounds.

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

    SciTech Connect

    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.

  12. 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.

  13. 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(⁎)).

  14. First principles nuclear magnetic resonance signatures of graphene oxide.

    PubMed

    Lu, Ning; Huang, Ying; Li, Hai-bei; Li, Zhenyu; Yang, Jinlong

    2010-07-21

    Nuclear magnetic resonance (NMR) has been widely used in graphene oxide (GO) structure studies. However, the detailed relationship between its spectroscopic features and the GO structural configuration remains elusive. Based on first principles (13)C chemical shift calculations using the gauge including projector augmented waves method, we provide a reliable spectrum-structure connection. The (13)C chemical shift in GO is found to be very sensitive to the atomic environment, even for the same type of oxidation groups. Factors determining the chemical shifts of epoxy and hydroxy groups have been discussed. GO structures previously reported in the literature have been checked from the NMR point of view. The energetically favorable hydroxy chain structure is not expected to be widely existed in real GO samples according to our NMR simulations. The epoxy pair species we proposed previously is also supported by chemical shift calculations.

  15. First principles nuclear magnetic resonance signatures of graphene oxide

    NASA Astrophysics Data System (ADS)

    Lu, Ning; Huang, Ying; Li, Hai-bei; Li, Zhenyu; Yang, Jinlong

    2010-07-01

    Nuclear magnetic resonance (NMR) has been widely used in graphene oxide (GO) structure studies. However, the detailed relationship between its spectroscopic features and the GO structural configuration remains elusive. Based on first principles C13 chemical shift calculations using the gauge including projector augmented waves method, we provide a reliable spectrum-structure connection. The C13 chemical shift in GO is found to be very sensitive to the atomic environment, even for the same type of oxidation groups. Factors determining the chemical shifts of epoxy and hydroxy groups have been discussed. GO structures previously reported in the literature have been checked from the NMR point of view. The energetically favorable hydroxy chain structure is not expected to be widely existed in real GO samples according to our NMR simulations. The epoxy pair species we proposed previously is also supported by chemical shift calculations.

  16. Scaling in biological nuclear magnetic resonance spectral distributions.

    PubMed Central

    Lacelle, S

    1986-01-01

    A statistical analysis of the distribution of the eigenvalues of the chemical shift interaction as detected by nuclear magnetic resonance (NMR) spectroscopy in large biological systems is presented in the light of random matrix theory. A power law dependence is experimentally observed for the distribution of the number of eigenvalues, N, of the shielding hamiltonian with epsilon i less than or equal to E as a function of the energy E. From this cumulative distribution of energy levels, N(E), we also obtain a density of states rho(E). The exponent of the energy variation of N(E) and rho(E) are correlated with the dimensionality of the molecular system. A crossover in the values of the exponents is found in passing from low to higher energy in the spectra. Our method classifies and reduces the chemical shift data base of proteins and also demonstrates a degree of regularity in seemingly irregular spectral patterns. PMID:3730504

  17. 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.

  18. 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.

  19. 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

  20. Blood species discrimination using proton nuclear magnetic resonance spectroscopy.

    PubMed

    Zailer, Elina; Diehl, Bernd W K; Monakhova, Yulia B

    2016-11-25

    Blood species identification is an important challenge in forensic science. Conventional methods used for blood species analysis are destructive and associated with time-consuming sample preparation steps. Nuclear magnetic resonance (NMR) spectroscopy is known for its nondestructive properties and fast results. This research study presents a proton ((1)H) NMR method to discriminate blood species including human, cat, dog, elephant, and bison. Characteristic signals acting as markers are observed for each species. Moreover, the data are evaluated by principle component analysis (PCA) and support vector machines (SVM). A 100% correct species recognition between human and nonhuman species is achieved using radial basis kernel function (RBF) and standardized data. The research study shows that (1)H NMR spectroscopy is a powerful tool for differentiating human and nonhuman blood showing a great significance to forensic science.

  1. 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.

  2. Nuclear magnetic resonance of iron and copper disease states

    SciTech Connect

    Runge, V.M.; Clanton, J.A.; Smith, F.W.; Hutchison, J.; Mallard, J.; Partain, C.L.; James, A.E. Jr.

    1983-11-01

    The tissue levels of paramagnetic ions are an important factor in the determination of T/sub 1/ values as observed by nuclear magnetic resonance (NMR) imaging. The increased levels of iron present in human disease states such as hemochromatosis lead to decreased T/sub 1/ values. The mean liver T/sub 1/ of three patients with iron storage disease was determined to be 130 msec, significantly different from the value of 154 msec, the mean for 14 normal controls. Whether NMR will be able to detect the increased copper levels in liver and brain in Wilson disease remains for further clinical trials to evaluate. NMR imaging, however, does serve as a noninvasive method for the diagnosis of states of iron overload and as a technique to follow progression of disease or response to medical therapy.

  3. /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.

  4. 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.

  5. Nuclear magnetic resonance probes of membrane biophysics: Structure and dynamics

    NASA Astrophysics Data System (ADS)

    Leftin, Avigdor

    The phospholipid membrane is a self-assembled, dynamic molecular system that may exist alone in association with only water, or in complex systems comprised of multiple lipid types and proteins. In this dissertation the intra- and inter-molecular forces responsible for the atomistic, molecular and collective equilibrium structure and dynamics are studied by nuclear magnetic resonance spectroscopy (NMR). The multinuclear NMR measurements and various experimental techniques are able to provide data that enable the characterization of the hierarchical spatio-temporal organization of the phospholipid membrane. The experimental and theoretical studies conducted target membrane interactions ranging from model systems composed of only water and lipids, to multiple component domain forming membranes that are in association with peripheral and trans-membrane proteins. These measurements consisit of frequency spectrum lineshapes and nuclear-spin relaxation rates obtained using 2H NMR, 13C NMR, 31P NMR and 1H NMR. The changes of these experimental observables are interpreted within a statistical thermodynamic framework that allows the membrane structure, activation energies, and correlation times of motion to be determined. The cases presented demonstrate how fundamental principles of NMR spectroscopy may be applied to a host of membranes, leading to the biophysical characterization of membrane structure and dynamics.

  6. The Electric Giant Resonances

    NASA Astrophysics Data System (ADS)

    van der Woude, A.

    The following sections are included: * Introduction * Experimental Methods to Study Giant Resonances * Introduction * The Tools * Introduction * Tools for Isoscalar Scattering * INELASTIC α-SCATTERING * INELASTIC PROTON SCATTERING * Tools for Isovector Excitations * γ-ABSORPTION AND PARTICLE CAPTURE REACTIONS * CHARGE EXCHANGE REACTIONS - THE (π+, π0) REACTION * Tools For Isoscalar And Isovector Excitations * INELASTIC ELECTRON SCATTERING * GIANT RESONANCE EXCITATION BY FAST HEAVY IONS * From Multipole Cross Section To Multipole Strength * The Electric Isoscalar Resonances * The Isoscalar Giant Monopole Resonance * Systematics on the GMR * Compressibility and the Giant Monopole Resonance * Introduction * The Compressibility of nuclear matter from the GMR energies * Discussion * The Isoscalar Giant Quadrupole Resonance * General Trends In Medium-Heavy and Heavy Nuclei * The GQR In Light Nuclei * The Isoscalar 3- Strength, LEOR and HEOR * Isoscalar 4+ Strength * Miscellaneous; Isoscalar 1- and L > 4-Strength * The Electric Isovector Giant Resonances * The Isovector Giant Dipole Resonance: GDR * The Isovector Giant Monopole Resonances: IVGMR * The Isovector Quadrupole Resonance: IVGQR * The Effect of Ground State Deformation on the Shape of Giant Resonance: Microscopic Picture * Giant Resonances Built on Excited States * Introduction * Capture Reactions on Light Nuclei * Statistical decay of GDR γ Emission in Heavy Compound Systems * Introduction * Theoretical Predictions * Some Experimental Results * Summary and Outlook * Acknowledgements * General References * References

  7. The Science of Nuclear Materials Detection using gamma-ray beams: Nuclear Resonance Fluorescence

    NASA Astrophysics Data System (ADS)

    Ohgaki, Hideaki

    2014-09-01

    An atomic nucleus is excited by absorption of incident photons with an energy the same as the excitation energy of the level, and subsequently a gamma-ray is emitted as it de-excites. This phenomenon is called Nuclear Resonance Fluorescence and mostly used for studies on Nuclear Physics field. By measuring the NRF gamma-rays, we can identify nuclear species in any materials because the energies of the NRF gamma-rays uniquely depend on the nuclear species. For example, 235U has an excitation level at 1733 keV. If we irradiate a material including 235U with a gamma-ray tuned at this excitation level, the material absorbs the gamma-ray and re-emits another gamma-ray immediately to move back towards the ground state. Therefore we can detect the 235U by measuring the re-emitted (NRF) gamma-rays. Several inspection methods using gamma-rays, which can penetrate a thick shielding have been proposed and examined. Bertozzi and Ledoux have proposed an application of nuclear resonance fluorescence (NRF) by using bremsstrahlung radiations. However the signal-to-noise (SN) ratio of the NRF measurement with the bremsstrahlung radiation is, in general, low. Only a part of the incident photons makes NRF with a narrow resonant band (meV-eV) whereas most of incident radiation is scattered by atomic processes in which the reaction rate is higher than that of NRF by several orders of magnitudes and causes a background. Thus, the NRF with a gamma-ray quasi-monochromatic radiation beam is proposed. The monochromatic gamma-rays are generated by using laser Compton scattering (LCS) of electrons and intense laser photons by putting a collimator to restrict the gamma-ray divergence downstream. The LCS gamma-ray, which is energy-tunable and monochromatic, is an optimum apparatus for NRF measurements We have been conducted NRF experiment for nuclear research, especially with high linear polarized gamma-ray generated by LCS, to survey the distribution of M1 strength in MeV region in LCS

  8. New Approaches to Quantum Computing using Nuclear Magnetic Resonance Spectroscopy

    SciTech Connect

    Colvin, M; Krishnan, V V

    2003-02-07

    The power of a quantum computer (QC) relies on the fundamental concept of the superposition in quantum mechanics and thus allowing an inherent large-scale parallelization of computation. In a QC, binary information embodied in a quantum system, such as spin degrees of freedom of a spin-1/2 particle forms the qubits (quantum mechanical bits), over which appropriate logical gates perform the computation. In classical computers, the basic unit of information is the bit, which can take a value of either 0 or 1. Bits are connected together by logic gates to form logic circuits to implement complex logical operations. The expansion of modern computers has been driven by the developments of faster, smaller and cheaper logic gates. As the size of the logic gates become smaller toward the level of atomic dimensions, the performance of such a system is no longer considered classical but is rather governed by quantum mechanics. Quantum computers offer the potentially superior prospect of solving computational problems that are intractable to classical computers such as efficient database searches and cryptography. A variety of algorithms have been developed recently, most notably Shor's algorithm for factorizing long numbers into prime factors in polynomial time and Grover's quantum search algorithm. The algorithms that were of only theoretical interest as recently, until several methods were proposed to build an experimental QC. These methods include, trapped ions, cavity-QED, coupled quantum dots, Josephson junctions, spin resonance transistors, linear optics and nuclear magnetic resonance. Nuclear magnetic resonance (NMR) is uniquely capable of constructing small QCs and several algorithms have been implemented successfully. NMR-QC differs from other implementations in one important way that it is not a single QC, but a statistical ensemble of them. Thus, quantum computing based on NMR is considered as ensemble quantum computing. In NMR quantum computing, the spins with

  9. Nuclear magnetic resonance studies of macroscopic morphology and dynamics

    SciTech Connect

    Barrall, Geoffrey Alden

    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.

  10. Electron-nuclear-nuclear triple resonance of cis-rich polyacetylene —Evidence for negative spin sites of soliton

    NASA Astrophysics Data System (ADS)

    Kuroda, S.; Shirakawa, H.

    1991-03-01

    Electron-nuclear double resonance (ENDOR) and electron-nuclear-nuclear triple resonance (TRIPLE) spectra of stretch-oriented cis-rich polyacetylene at low temperatures show clear spectral turning points when the external magnetic field is parallel to the stretch direction. The difference between ENDOR and TRIPLE spectra, depending on the pumping frequency of the latter, provide direct evidence that the turning points are associated with the negative spin sites of the soliton, arising from electron correlation effect, as predicted from our previous ENDOR analysis.

  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. 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.

  13. 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.

  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. Nuclear Resonance Fluorescence for Material Verification in Dismantlement

    SciTech Connect

    Warren, Glen A.; Detwiler, Rebecca S.

    2011-10-01

    Nuclear resonance fluorescence (NRF) is a well-established physical process that provides an isotope-specific signature that can be exploited for isotopic detection and characterization of samples. Pacific Northwest National Laboratory has been investigating possible applications of NRF for national security. Of the investigated applications, the verification of material in the dismantlement process is the most promising. Through a combination of benchmarking measurements and radiation transport modeling, we have shown that NRF techniques with existing bremsstrahlung photon sources and a modest detection system can be used to detect highly enriched uranium in the quantities and time limits relevant to the dismantlement process. Issues such as orientation, placement and material geometry do not significantly impact the sensitivity of the technique. We have also investigated how shielding of the uranium would be observed through non-NRF processes to enable the accurate assay of the material. This paper will discuss our findings on how NRF and photon-interrogation techniques may be applied to the material verification in the dismantlement process.

  16. 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.

  17. High-resolution two-field nuclear magnetic resonance spectroscopy.

    PubMed

    Cousin, Samuel F; Charlier, Cyril; Kadeřávek, Pavel; Marquardsen, Thorsten; Tyburn, Jean-Max; Bovier, Pierre-Alain; Ulzega, Simone; Speck, Thomas; Wilhelm, Dirk; Engelke, Frank; Maas, Werner; Sakellariou, Dimitrios; Bodenhausen, Geoffrey; Pelupessy, Philippe; Ferrage, Fabien

    2016-12-07

    Nuclear magnetic resonance (NMR) is a ubiquitous branch of spectroscopy that can explore matter at the scale of an atom. Significant improvements in sensitivity and resolution have been driven by a steady increase of static magnetic field strengths. However, some properties of nuclei may be more favourable at low magnetic fields. For example, transverse relaxation due to chemical shift anisotropy increases sharply at higher magnetic fields leading to line-broadening and inefficient coherence transfers. Here, we present a two-field NMR spectrometer that permits the application of rf-pulses and acquisition of NMR signals in two magnetic centres. Our prototype operates at 14.1 T and 0.33 T. The main features of this system are demonstrated by novel NMR experiments, in particular a proof-of-concept correlation between zero-quantum coherences at low magnetic field and single quantum coherences at high magnetic field, so that high resolution can be achieved in both dimensions, despite a ca. 10 ppm inhomogeneity of the low-field centre. Two-field NMR spectroscopy offers the possibility to circumvent the limits of high magnetic fields, while benefiting from their exceptional sensitivity and resolution. This approach opens new avenues for NMR above 1 GHz.

  18. 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.

  19. Nuclear Magnetic Resonance Spectroscopy-Based Identification of Yeast.

    PubMed

    Himmelreich, Uwe; Sorrell, Tania C; Daniel, Heide-Marie

    2017-01-01

    Rapid and robust high-throughput identification of environmental, industrial, or clinical yeast isolates is important whenever relatively large numbers of samples need to be processed in a cost-efficient way. Nuclear magnetic resonance (NMR) spectroscopy generates complex data based on metabolite profiles, chemical composition and possibly on medium consumption, which can not only be used for the assessment of metabolic pathways but also for accurate identification of yeast down to the subspecies level. Initial results on NMR based yeast identification where comparable with conventional and DNA-based identification. Potential advantages of NMR spectroscopy in mycological laboratories include not only accurate identification but also the potential of automated sample delivery, automated analysis using computer-based methods, rapid turnaround time, high throughput, and low running costs.We describe here the sample preparation, data acquisition and analysis for NMR-based yeast identification. In addition, a roadmap for the development of classification strategies is given that will result in the acquisition of a database and analysis algorithms for yeast identification in different environments.

  20. Updated methodology for nuclear magnetic resonance characterization of shales

    NASA Astrophysics Data System (ADS)

    Washburn, Kathryn E.; Birdwell, Justin E.

    2013-08-01

    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.

  1. Using Nuclear Resonance Fluorescence for Nondestructive Isotopic Analysis

    SciTech Connect

    Ludewigt, Bernhard A.; Mozin, Vladimir; Haefner, Andrew; Quiter, Brian

    2010-07-14

    Nuclear resonance fluorescence (NRF) has been studied as one of the nondestructive analysis (NDA) techniques currently being investigated by a multi-laboratory collaboration for the determination of Pu mass in spent fuel. In NRF measurements specific isotopes are identified by their characteristic lines in recorded gamma spectra. The concentration of an isotope in a material can be determined from measured NRF signal intensities if NRF cross sections and assay geometries are known. The potential of NRF to quantify isotopic content and Pu mass in spent fuel has been studied. The addition of NRF data to MCNPX and an improved treatment of the elastic photon scattering at backward angles has enabled us to more accurately simulate NRF measurements on spent fuel assemblies. Using assembly models from the spent fuel assembly library generated at LANL, NRF measurements are simulated to find the best measurement configurations, and to determine measurement sensitivities and times, and photon source and gamma detector requirements. A first proof-of-principal measurement on a mock-up assembly with a bremsstrahlung photon source demonstrated isotopic sensitivity to approximately 1% limited by counting statistics. Data collection rates are likely a limiting factor of NRF-based measurements of fuel assemblies but new technological advances may lead to drastic improvements.

  2. 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

  3. Optically Pumped Nuclear Magnetic Resonance in the Quantum Hall Regimes

    NASA Astrophysics Data System (ADS)

    Barrett, S. E.; Khandelwal, P.; Kuzma, N. N.; Pfeiffer, L. N.; West, K. W.

    1997-03-01

    Optical pumping enables the direct detection of the nuclear magnetic resonance signal of ^71Ga nuclei located in an electron doped GaAs quantum well.footnote S. E. Barrett et al., Phys. Rev. Lett. 72, 1368 (1994) Using this technique, measurements of the Knight shift (K_S)footnote S. E. Barrett et al., Phys. Rev. Lett. 74, 5112 (1995) and spin-lattice relaxation time (T_1)footnote R. Tycko et al., Science 268, 1460 (1995) have been carried out in the Quantum Hall regimes. This talk will focus on our latest measurements of KS and T1 near Landau level filling ν=1, which extend our earlier results to higher magnetic fields (B=12 Tesla) and lower temperatures (T < 1 Kelvin). We will compare these results to the theoretical predictionsfootnote S. L. Sondhi et al., Phys. Rev. B 47, 16419 (1993); H. A. Fertig et al., Phys. Rev. B 50, 11018 (1994) that the charged excitations of the ν = 1 ground state are novel spin textures called skyrmions. The current status of this picture will be discussed.

  4. Two-dimensional nuclear magnetic resonance of quadrupolar systems

    SciTech Connect

    Wang, Shuanhu

    1997-09-01

    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.

  5. Conformational characterization of ceramides by nuclear magnetic resonance spectroscopy.

    PubMed Central

    Li, Li; Tang, Xiaoping; Taylor, K Grant; DuPré, Donald B; Yappert, M Cecilia

    2002-01-01

    Ceramide (Cer) has been identified as an active lipid second messenger in the regulation of cell growth, differentiation, and apoptosis. Its analog, dihydroceramide, without the 4 to 5 trans double bond in the sphingoid backbone lacks these biological effects. To establish the conformational features that distinguish ceramide from its analogs, nuclear magnetic resonance spectral data were acquired for diluted samples of ceramides (C2- and C18-Cer), dihydroceramide (C16-DHCer), and deoxydihydroceramide (C18-DODHCer). Our results suggest that in both C2- and C18-Cer, an H-bond network is formed in which the amide proton NH is donated to the OH groups on carbons C1 and C3 of the sphingosine backbone. Two tightly bound water molecules appear to stabilize this network by participating in flip-flop interactions with the hydroxyl groups. In DHCer, the lack of the trans double bond leads to a conformational distortion of this H-bonding motif. Without the critical double bond, the degree with which water molecules stabilize the H bonds between the two OH groups of the sphingolipid is reduced. This structural alteration might preclude the participation of DHCer in signaling-related interactions with cellular targets. PMID:11916863

  6. 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.

  7. Multinuclear nuclear magnetic resonance spectroscopic study of cartilage proteoglycans

    SciTech Connect

    Lerner, L.

    1985-01-01

    Hyaline cartilage is a composite material whose major function is to withstand compression while retaining flexibility. Its mechanical properties are affected by tissue hydration and ionic composition. Models of the mechanical behavior of cartilage have incorporated certain assumptions about the interactions of the major components of cartilage: collagen, proteoglycans, water, and cations. To determine the validity of these assumption, the authors have used nuclear magnetic resonance spectroscopy (NMR). Two approaches have been used: (a) natural abundance carbon-13 NMR; and (b) NMR of sodium-23, potassium-39, magnesium-25, and calcium-43. Evidence from studies in intact tissues are reinforced by extensive measurements on solutions of proteoglycans and other relevant macromolecules. Based on the measurements of NMR relaxation rates and lineshapes reported here, it is concluded that neither sodium nor potassium interact strongly with bovine nasal proteoglycan aggregates or their substituent glycosaminoglycan chains in solution. Proteoglycans do bind magnesium and calcium. Therefore there is a qualitative difference between monovalent and divalent cations, which is not taken into account by polyelectrolyte models or models for the ionic dependence of mechanical properties. Cation binding to heparin, which has a higher charge density than cartilage proteoglycans, was also studied. The results presented here establish that heparin binds sodium, magnesium, and calcium.

  8. Nuclear magnetic resonance metabolomics of iron deficiency in soybean leaves.

    PubMed

    Lima, Marta R M; Diaz, Sílvia O; Lamego, Inês; Grusak, Michael A; Vasconcelos, Marta W; Gil, Ana M

    2014-06-06

    Iron (Fe) deficiency is an important agricultural concern that leads to lower yields and crop quality. A better understanding of the condition at the metabolome level could contribute to the design of strategies to ameliorate Fe-deficiency problems. Fe-sufficient and Fe-deficient soybean leaf extracts and whole leaves were analyzed by liquid (1)H nuclear magnetic resonance (NMR) and high-resolution magic-angle spinning NMR spectroscopy, respectively. Overall, 30 compounds were measurable and identifiable (comprising amino and organic acids, fatty acids, carbohydrates, alcohols, polyphenols, and others), along with 22 additional spin systems (still unassigned). Thus, metabolite differences between treatment conditions could be evaluated for different compound families simultaneously. Statistically relevant metabolite changes upon Fe deficiency included higher levels of alanine, asparagine/aspartate, threonine, valine, GABA, acetate, choline, ethanolamine, hypoxanthine, trigonelline, and polyphenols and lower levels of citrate, malate, ethanol, methanol, chlorogenate, and 3-methyl-2-oxovalerate. The data indicate that the main metabolic impacts of Fe deficiency in soybean include enhanced tricarboxylic acid cycle activity, enhanced activation of oxidative stress protection mechanisms and enhanced amino acid accumulation. Metabolites showing accumulation differences in Fe-starved but visually asymptomatic leaves could serve as biomarkers for early detection of Fe-deficiency stress.

  9. 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.

  10. 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.

  11. Distinguishing Carbonate Reservoir Pore Facies with Nuclear Magnetic Resonance Measurements

    SciTech Connect

    Genty, Coralie; Jensen, Jerry L. Ahr, Wayne M.

    2007-03-15

    Characterization of carbonate rocks may involve identifying the important pore types which are present. In the past, this task has required detailed petrographic analysis of many core samples. Here, we describe a method which uses nuclear magnetic resonance (NMR) measurements to reduce the amount of petrographic analysis needed for porosity typing of carbonate reservoir rocks.For a rock sample which has been measured with NMR, our method decomposes the log(T{sub 2}) spectrum into at most three Gaussian-shaped components and gives a set of nine parameters. Two characteristic quantities having geological significance are extracted from the nine parameters. Values of the two quantities are compared with a reference set, established from samples having both NMR and petrographic evaluations of porosity types. We use a Bayesian approach to the classification of the dominant porosity type.Tests of our method on 103 samples show a correct prediction in 60 to 90 percent of the samples. The lower success rate was obtained for samples with five porosity types from three fields; the higher success rate obtained with samples with three porosity types from one well. The use of geologically significant quantities extracted from the decomposition gives comparable success rate to those obtained using a standard, non-geological approach such as canonical variates.

  12. 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

  13. Updated methodology for nuclear magnetic resonance characterization of shales.

    PubMed

    Washburn, Kathryn E; Birdwell, Justin E

    2013-08-01

    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.

  14. New Versions of Terahertz Radiation Sources for Dynamic Nuclear Polarization in Nuclear Magnetic Resonance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Bratman, V. L.; Kalynov, Yu. K.; Makhalov, P. B.; Fedotov, A. E.

    2014-01-01

    Dynamic nuclear polarization in strong-field nuclear magnetic resonance (NMR) spectroscopy requires terahertz radiation with moderate power levels. Nowadays, conventional gyrotrons are used almost exclusively to generate such radiation. In this review paper, we consider alternative variants of electronic microwave oscillators which require much weaker magnetic fields for their operation, namely, large-orbit gyrotrons operated at high cyclotron-frequency harmonics and Čerenkov-type devices, such as a backward-wave oscillator and a klystron frequency multiplier with tubular electron beams. Additionally, we consider the possibility to use the magnetic field created directly by the solenoid of an NMR spectrometer for operation of both the gyrotron and the backward-wave oscillator. Location of the oscillator in the spectrometer magnet makes it superfluous to use an additional superconducting magnet creating a strong field, significantly reduces the length of the radiation transmission line, and, in the case of Čerenkov-type devices, allows one to increase considerably the output-signal power. According to our calculations, all the electronic devices considered are capable of ensuring the power required for dynamic nuclear polarization (10 W or more) at a frequency of 260 GHz, whereas the gyrotrons, including their versions proposed in this paper, remain a single option at higher frequencies.

  15. 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.

  16. 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).

  17. Nuclear magnetic resonance spectra for l > 1 spins in dynamically heterogeneous systems with chemical exchange among environments.

    PubMed

    Zhang, H; Bryant, R G

    1995-06-01

    Nuclear magnetic resonance spectra for nuclei with spin l > 1 are considered in cases in which the observed nucleus may sample a rotationally immobilized and an isotropic environment that are coupled by a chemical exchange process. Spectra are simulated for the central (1/2, -1/2) transition for a 3/2 nucleus as a function of the concentrations of the two environments and as a function of the exchange rate between them. It is shown that a crucial feature determining the shape of the observable spectra is the spatial extent or the local order in the immobilized phase. In the case for which all rotationally immobilized sites sampled by the exchanging nucleus are identically oriented but where there is a distribution of these microdomain orientations with respect to the magnetic field direction, a powder pattern for the central transition is observed that carries whatever dynamic information may be derived from it. In the fast exchange limit, the width of the powder pattern scales inversely with the concentration of the isotropic environment as usual. In the intermediate exchange regimes, a complex line shape results that may mask the anisotropic character of the spectrum. In the slow exchange limit, superposition of the spectral contributions results; however, if the isotropic environment concentration is significantly larger than the anisotropic environment concentration, the anisotropic contribution is very difficult to detect because of the dynamic range problem and the possibly large difference in the effective line widths. In the case for which the exchanging nucleus samples a considerable distribution of rotationally immobilized site orientations, the anisotropic character of the spectrum is lost and a super-Lorentzian line shape results. These effects are demonstrated experimentally by 35Cl nuclear magnetic resonance spectra obtained on a lamellar liquid crystal that is modified with the addition of a thiolmercurate to provide a site of large quadrupole

  18. 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

  19. Novel nuclear magnetic resonance techniques for studying biological molecules

    SciTech Connect

    Laws, David Douglas

    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 (Φ/Ψ) dihedral angles by comparing experimentally determined 13Ca, 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 α-helical and β-sheet conformers in the solid state, the aggregates formed from the PrP 89-143 mutants appear to be mostly β-sheet.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    The water-endofullerene H2O@C60 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 H2O 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 H2O molecules is catalysed by 13C nuclei present in the cages.

  1. 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.

  2. 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.

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

    PubMed

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

    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.

  4. 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

  5. Optically Pumped Nuclear Magnetic Resonance in the Quantum Hall Regimes

    NASA Astrophysics Data System (ADS)

    Barrett, Sean E.

    1998-03-01

    Optical pumping enables the direct detection of the nuclear magnetic resonance signal of ^71Ga nuclei located in an electron doped GaAs quantum well.footnote S. E. Barrett et al., Phys. Rev. Lett. 72, 1368 (1994) This OPNMR technique was previously used to measure the Knight shift (K_S)footnote S. E. Barrett et al., Phys. Rev. Lett. 74, 5112 (1995) and spin-lattice relaxation time (T_1)footnote R. Tycko et al., Science 268, 1460 (1995) near Landau level filling ν=1, which provided the first experimental support for the theoretical predictionsfootnote S. L. Sondhi et al., Phys. Rev. B 47, 16419 (1993); H. A. Fertig et al., Phys. Rev. B 50, 11018 (1994) that the charged excitations of the ν = 1 ground state are novel spin textures called skyrmions. We have recently demonstrated that OPNMR is possible in fields up to B=12 Tesla, and temperatures down to T= 0.3 K, making it a viable new probe of the Fractional Quantum Hall Regime. In this talk we will present our latest OPNMR measurements near Landau level filling ν=1/3, which include the first direct measurement of the electron spin polarization at ν=1/3. The spin polarization drops as the filling factor is varied away from ν=1/3, indicating that the quasiparticles and quasiholes are not fully spin-polarized. We will also show how the NMR lineshape away from ν=1/3 changes dramatically at low temperatures, which is due to slowing of the electron dynamics, and a reduction in the motional narrowing of the NMR line. The current understanding of these results will be discussed.

  6. 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

  7. Nuclear magnetic resonance data of C2H10OSi2

    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'.

  8. Nuclear magnetic resonance data of C8H24OSi4Te

    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'.

  9. Quadrupole interactions: NMR, NQR, and in between from a single viewpoint.

    PubMed

    Bain, Alex D

    2017-03-01

    Nuclear spins with quantum numbers >1/2 can interact with a static magnetic field, or a local electric field gradient, to produce quantized energy levels. If the magnetic field interaction dominates, we are doing nuclear magnetic resonance (NMR). If the interaction of the nuclear electric quadrupole with electric field gradients is much stronger, this is nuclear quadrupole resonance (NQR). The two are extremes of a continuum, as the ratio of one interaction to the other changes. In this work, we look at this continuum from a single, unified viewpoint based on a Liouville-space approach: the direct method. This method does not require explicit operators and their commutators, unlike Hamiltonian methods. We derive both the quadrupole-perturbed NMR solution and also the Zeeman-perturbed NQR results. Furthermore, we examine the polarization of these signals, because this is different between pure NMR and pure NQR spectroscopy. Spin 3/2 is the focus here, but the approach is perfectly general and can be applied to any spin. Copyright © 2016 John Wiley & Sons, Ltd.

  10. Two-Dimensional Isotope Imaging of Radiation Shielded Materials Using Nuclear Resonance Fluorescence

    NASA Astrophysics Data System (ADS)

    Toyokawa, Hiroyuki; Ohgaki, Hideaki; Hayakawa, Takehito; Kii, Toshiteru; Shizuma, Toshiyuki; Hajima, Ryoichi; Kikuzawa, Nobuhiro; Masuda, Kai; Kitatani, Fumito; Harada, Hideo

    2011-10-01

    A novel method for two-dimensional (2D) imaging of a specific isotope in a material, which is hidden by a thick radiation shield is presented. Nuclear resonance fluorescence and the laser Compton scattering are used in the present method. We measured γ-rays of 5512 keV from the nuclear resonance fluorescence of 208Pb at several points, and obtained a 2D image of isotope distribution.

  11. Doorway-state analysis of the fine structure in the giant quadrupole resonance in 208Pb observed in inelastic electron scattered

    NASA Astrophysics Data System (ADS)

    Winchenbach, J.; Pingel, K.; Holzwarth, G.; Kühner, G.; Richter, A.

    1983-11-01

    The fine structure observed in high resolution inelastic electron scattering data obtained at DALINAC for 208Pb in the excitation energy range of the giant quadrupole resonance (GQR) has been analysed under the assumption that the measured strongly fragmented E2 strength distribution is due to the coupling of one or two doorway states to a large number of more complicated states. The coupling matrix elements derived from the analysis allow the determination of the escape and spreading widths Γ ↑ and Γ ↓, the excitation energies Ed, the energy shifts ΔEd, and their energy dependence, for the underlying doorways.

  12. 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

  13. Cu nuclear magnetic resonance study of charge and spin stripe order in La1.875Ba0.125CuO4

    NASA Astrophysics Data System (ADS)

    Pelc, D.; Grafe, H.-J.; Gu, G. D.; Požek, M.

    2017-02-01

    We present a Cu nuclear magnetic/quadrupole resonance study of the charge stripe ordered phase of LBCO, with detection of previously unobserved ("wiped-out") signal. We show that spin-spin and spin-lattice relaxation rates are strongly enhanced in the charge ordered phase, explaining the apparent signal decrease in earlier investigations. The enhancement is caused by magnetic, rather than charge fluctuations, conclusively confirming the long-suspected assumption that spin fluctuations are responsible for the wipeout effect. Observation of the full Cu signal enables insight into the spin and charge dynamics of the stripe-ordered phase, and measurements in external magnetic fields provide information on the nature and suppression of spin fluctuations associated with charge order. We find glassy spin dynamics, in agreement with previous work, and incommensurate static charge order with charge modulation amplitude similar to other cuprate compounds, suggesting that the amplitude of charge stripes is universal in the cuprates.

  14. 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…

  15. Improving the Assay of 239Pu in Spent and Melted Fuel Using the Nuclear Resonance Fluorescence Integral Resonance Transmission Method

    NASA Astrophysics Data System (ADS)

    Angell, C. T.; Hayakawa, T.; Shizuma, T.; Hajima, R.; Quiter, B. J.; Ludewigt, B. A.; Karwowski, H.; Rich, G.

    2015-10-01

    Non-destructive assay (NDA) of 239Pu in spent nuclear fuel is possible using the isotope-specific nuclear resonance fluorescence (NRF) integral resonance transmission (IRT) method. The IRT method measures the absorption of photons from a quasi-monoenergetic γ-ray beam due to all resonances in the energy width of the beam. According to calculations the IRT method could greatly improve assay times for 239Pu in nuclear fuel. To demonstrate and verify the IRT method, the IRT signature was first measured in 181Ta, whose nuclear resonant properties are similar to those of 239Pu, and then measured in 239Pu. These measurements were done using the quasi-monoenergetic beam at the High Intensity γ-ray Source (HIγS) in Durham, NC, USA. The IRT signature was observed as a decrease in scattering strength when the same isotope material was placed upstream of the scattering target. The results confirm the validity of the IRT method in both 181Ta and 239Pu.

  16. 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.

  17. 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

  18. 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

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

    SciTech Connect

    Goodson, Boyd McLean

    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.

  20. Nuclear Magnetic Resonance Nondestructive Evaluation of Composite Materials

    DTIC Science & Technology

    1990-04-09

    Pat. Appl. EP 26265, 8 Apr 1981, 13 pp. (1981). 9. A. N. Garroway , J. Baum, M. G. Munowitz, and A. Pines, NMR Imaging in Solids by Multiple-Quantum...Resonance, J. Magn. Reson. 60(2), 337-41 (1984). 10. J. Baum, A. N. Garroway , M. Munowitz, and A. Pines, Multiple-Quantum NMR in Solids: Application to... Garroway , NMR Images of Solids, J. Magn. Reson. 66(3), 530-5 (1986). 28. J. B. Miller and A. N. Garroway , Removal of Static Field Inhomogeneity and

  1. 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.

  2. 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.

    PubMed

    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.

  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. In-Situ Real Time Detection of Explosive/Chemical Compounds in Mines Using Nuclear Quadrupole Resonance (NQR)

    DTIC Science & Technology

    2012-02-23

    mineflelds in Bosnia, and blind tests on TNT and RDX AP and AT mines were carried out at Ft. Leonard Wood. The system detected 100% of all mines in the...three tests in the fmal year, with a false alarm rate less than 1%. Much of the knowledge gained has been only partly implemented in prototypes to date...16 4.1.2 Test on live Explosives

  5. 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.

  6. 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

  7. Nuclear Molecular Resonances in Heavy-Ion Collisions.

    ERIC Educational Resources Information Center

    Erb, Karl A.; Bromley, D. Allan

    1979-01-01

    Explains that some nuclear scattering phenomena can be attributed to states in which two nuclei are bound to each other at their surfaces, revolving and vibrating for a time before coalescing or disintegrating. (Author/GA)

  8. Nuclear resonance reflection of synchrotron radiation from thin dysprosium films with different types of magnetic ordering

    NASA Astrophysics Data System (ADS)

    Andreeva, M. A.; Antropov, N. O.; Baulin, R. A.; Kravtsov, E. A.; Ryabukhina, M. V.; Yakunina, E. M.; Ustinov, V. V.

    2016-12-01

    Epitaxial thin films of dysprosium have been successfully synthesized by the method of high-vacuum magnetron sputtering and their structure and magnetic properties have been investigated. The opportunity of the nuclear resonance scattering for the investigation of nanostructures containing 161Dy has been considered; the specific features of the spectra of nuclear resonance reflectivity from the films have been analyzed on the energy and time scales at different orientations of the magnetic hyperfine field. The simulation of the angular dependences of nuclear resonance reflectivity for the case of spiral ordering in periodic structures containing 161Dy has been carried out. It has been shown that these dependences make it possible to uniquely determine the period of magnetic ordering.

  9. Design and development of a novel nuclear magnetic resonance detection for the gas phase ions by magnetic resonance acceleration technique

    NASA Astrophysics Data System (ADS)

    Fuke, K.; Tona, M.; Fujihara, A.; Sakurai, M.; Ishikawa, H.

    2012-08-01

    Nuclear magnetic resonance (NMR) technique is a well-established powerful tool to study the physical and chemical properties of a wide range of materials. However, presently, NMR applications are essentially limited to materials in the condensed phase. Although magnetic resonance was originally demonstrated in gas phase molecular beam experiments, no application to gas phase molecular ions has yet been demonstrated. Here, we present a novel principle of NMR detection for gas phase ions based on a "magnetic resonance acceleration" technique and describe the design and construction of an apparatus which we are developing. We also present an experimental technique and some results on the formation and manipulation of cold ion packets in a strong magnetic field, which are the key innovations to detect NMR signal using the present method. We expect this novel method to lead new realm for the study of mass-selected gas-phase ions with interesting applications in both fundamental and applied sciences.

  10. Quality assessment of layer-structured semiconductor single crystals by nuclear quadruple resonance method

    NASA Astrophysics Data System (ADS)

    Samila, Andriy; Khandozhko, Alexander; Lastivka, Galina; Politansky, Leonid; Khandozhko, Victor

    2015-11-01

    A method for quality assessment of layer-structured semiconductor single crystals (InSe, GaSe, GaS) grown in evacuated ampoules by the Bridgman technique is proposed. For this purpose, nuclear quadruple resonance method with a consecutive scanning of the entire sample volume and evaluation of crystal perfection by the resulting spectra is used. Effective interaction between high-frequency field and crystal and, accordingly, restriction of scanning area of sample under study is provided with the use of a two-way saddle-shaped coil for a nuclear quadruple resonance spectrometer.

  11. 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.

  12. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    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.

  14. Proton nuclear magnetic resonance studies of mast cell histamine

    SciTech Connect

    Rabenstein, D.L.; Ludowyke, R.; Lagunoff, D.

    1987-11-03

    The state of histamine in mast cells was studied by /sup 1/H NMR spectroscopy. Spectra were measured for histamine in situ in intact mast cells, for histamine in suspensions of mast cell granule matrices that had been stripped of their membranes, and for histamine in solutions of heparin. The /sup 1/H NMR spectrum of intact mast cells is relatively simple, consisting predominantly of resonances for intracellular histamine superimposed on a weaker background of resonances from heparin and proteins of the cells. All of the intracellular histamine contributes of the NMR signals, indicating it must be relatively mobile and not rigidly associated with the negatively charged granule matrix. Spectra for intracellular histamine and for histamine in granule matrices are similar, indicating the latter to be a reasonable model for the in situ situation. The dynamics of binding of histamine by granule matrices and by heparin are considerably different; exchange of histamine between the bulk water and the granule matrices is slow on the /sup 1/H NMR time scale, whereas exchange between the free and bound forms in heparin solution is fast. The chemical shifts of resonances for histamine in mast cells are pH dependent, decreasing as the intragranule pH increases without splitting or broadening. The results are interpreted to indicate that histamine in mast cells is relatively labile, with rapid exchange between histamine and pools of free histamine in water compartments confined in the granule matrix.

  15. Low-temperature nuclear magnetic resonance investigation of systems frustrated by competing exchange interactions

    NASA Astrophysics Data System (ADS)

    Roy, Beas

    This doctoral thesis emphasizes on the study of frustrated systems which form a very interesting class of compounds in physics. The technique used for the investigation of the magnetic properties of the frustrated materials is Nuclear Magnetic Resonance (NMR). NMR is a very novel tool for the microscopic study of the spin systems. NMR enables us to investigate the local magnetic properties of any system exclusively. The NMR experiments on the different systems yield us knowledge of the static as well as the dynamic behavior of the electronic spins. Frustrated systems bear great possibilities of revelation of new physics through the new ground states they exhibit. The vandates AA'VO(PO4)2 [AA' ≡ Zn2 and BaCd] are great prototypes of the J1-J2 model which consists of magnetic ions sitting on the corners of a square lattice. Frustration is caused by the competing nearest-neighbor (NN) and next-nearest neighbor (NNN) exchange interactions. The NMR investigation concludes a columnar antiferromagnetic (AFM) state for both the compounds from the sharp peak of the nuclear spin-lattice relaxation rate (1/T1) and a sudden broadening of the 31P-NMR spectrum. The important conclusion from our study is the establishment of the first H-P-T phase diagram of BaCdVO(PO4)2. Application of high pressure reduces the saturation field (HS) in BaCdVO(PO4)2 and decreases the ratio J2/J1, pushing the system more towards a questionable boundary (a disordered ground state) between the columnar AFM and a ferromagnetic ground state. A pressure up to 2.4 GPa will completely suppress HS. The Fe ions in the `122' iron-arsenide superconductors also sit on a square lattice thus closely resembling the J1-J2 model. The 75As-NMR and Nuclear Quadrupole Resonance (NQR) experiments are conducted in the compound CaFe2As2 prepared by two different heat treatment methods (`as-grown' and `annealed'). Interestingly the two samples show two different ground states. While the ground state of the `as

  16. 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

  17. [Nuclear magnetic resonance tomography of the temporomandibular joint].

    PubMed

    König, H; Spitzer, W J

    1986-05-01

    Because of its position, the temporomandibular joint is difficult to demonstrate by conventional radiological methods. Even the use of complex methods, such as arthro-tomography or CT, does not result in the satisfactory demonstration of the soft tissues and, in particular, of the articular disc. Magnetic resonance was carried out in 24 patients; it was possible to differentiate functional from morphological changes in the cartilage and these are discussed. Measurements were carried out during progressive opening of the mouth. This permits direct demonstration of reversible and irreversible cartilage displacement and of other changes in the joint and cartilages.

  18. Monopole, Quadrupole and Pairing: a Shell Model View

    NASA Astrophysics Data System (ADS)

    Zuker, A. P.

    The three main contributions to the nuclear Hamiltonian-monopole, quadrupole and pairing - are analyzed in a shell model context. The first has to be treated phenomenologically, while the other two can be reliably extracted from the realistic interactions. Due to simple scaling properties, the realistic quadrupole and pairing interactions eliminate the tendency to collapse of their conventional counterparts, while retaining their basic simplicity.

  19. Quadrupole ion traps.

    PubMed

    March, Raymond E

    2009-01-01

    The extraordinary story of the three-dimensional radiofrequency quadrupole ion trap, accompanied by a seemingly unintelligible theoretical treatment, is told in some detail because of the quite considerable degree of commercial success that quadrupole technology has achieved. The quadrupole ion trap, often used in conjunction with a quadrupole mass filter, remained a laboratory curiosity until 1979 when, at the American Society for Mass Spectrometry Conference in Seattle, George Stafford, Jr., of Finnigan Corp., learned of the Masters' study of Allison Armitage of a combined quadrupole ion trap/quadrupole mass filter instrument for the observation of electron impact and chemical ionization mass spectra of simple compounds eluting from a gas chromatograph. Stafford developed subsequently the mass-selective axial instability method for obtaining mass spectra from the quadrupole ion trap alone and, in 1983, Finnigan Corp. announced the first commercial quadrupole ion trap instrument as a detector for a gas chromatograph. In 1987, confinement of ions generated externally to the ion trap was demonstrated and, soon after, the new technique of electrospray ionization was shown to be compatible with the ion trap.

  20. Perspective on Advances in Resonance-Region Nuclear Modeling and Opportunities for Future Research

    SciTech Connect

    Dunn, Michael E; Larson, Nancy M; Derrien, Herve; Leal, Luiz C

    2007-01-01

    The advent of high-fidelity radiation-transport modeling capabilities, coupled with the need to analyze complex nuclear systems, has served to emphasize the importance of high-precision cross section data, including the associated covariance information. Due to the complex nature of resonance-region interactions, cross section data cannot be calculated directly from theory; rather, high-precision resonance-region cross section measurements must be made at facilities such as the Oak Ridge Electron Linear Accelerator (ORELA) at Oak Ridge National Laboratory (ORNL), Geel Electron Linear Accelerator (GELINA), Rensselaer Polytechnic Institute (RPI). To extract accurate cross section data from these measurements, detailed nuclear modeling of the measured data is performed to parameterize the cross section behavior in the resonance range. The objective of this paper is to highlight recent advances in resonance-region nuclear modeling with particular emphasis on the covariance analysis capabilities. Opportunities for future research are identified in an effort to stimulate further advances in the state of the art nuclear modeling capabilities.

  1. In vivo imaging of the rat anatomy with nuclear magnetic resonance.

    PubMed

    Hansen, G; Crooks, L E; Davis, P; De Groot, J; Herfkens, R; Margulis, A R; Gooding, C; Kaufman, L; Hoenninger, J; Arakawa, M; McRee, R; Watts, J

    1980-09-01

    Live rats were imaged by nuclear magnetic resonance (NMR). These images demonstrated fine detail and high object contrast. Motion artifacts are not apparent in 4-minute images, and major blood vessels are demonstrated as regions of low signal intensity because of blood flow. Selective contrast enhancement is possible by varying NMR imager accumulation parameters.

  2. 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...

  3. Exploration of the Use of Nuclear Magnetic Resonance for the Study of Ricin Toxicity in Cells

    DTIC Science & Technology

    2009-04-01

    ricin. 15. SUBJECT TERMS 3T3 Cells Ricinus communis Cell Toxicity Nuclear Magnetic Resonance NMR Ricin 16. SECURITY CLASSIFICATION OF: a. REPORT u...Ricin Preparation. The Ricin communis agglutinin II (ricin) stock solution was prepared by dialyzing ricin (Vector Laboratories, Burlingame, CA

  4. Interaction between adrenaline and dibenzo-18-crown-6: Electrochemical, nuclear magnetic resonance, and theoretical study

    NASA Astrophysics Data System (ADS)

    Yu, Zhang-Yu; Liu, Tao; Wang, Xue-Liang

    2014-12-01

    The interaction between adrenaline (Ad) and dibenzo-18-crown-6 (DB18C6) was studied by cyclic voltammetry, nuclear magnetic resonance spectroscopy, and the theoretical calculations, respectively. The results show that DB18C6 will affect the electron transfer properties of Ad. DB18C6 can form stable supramolecular complexes with Ad through ion-dipole and hydrogen bond interactions.

  5. 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.

  6. 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…

  7. Quantitative nuclear magnetic resonance to measure body composition in infants and children

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quantitative Nuclear Magnetic Resonance (QMR) is being used in human adults to obtain measures of total body fat (FM) with high precision. The current study assessed a device specially designed to accommodate infants and children between 3 and 50 kg (EchoMRI-AH™). Body composition of 113 infants and...

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

    SciTech Connect

    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.

  9. 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.

  10. 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…

  11. 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.

  12. Double-tuned single coil probe for nuclear magnetic resonance spectrometer

    SciTech Connect

    McKay, R.A.

    1984-05-01

    A double-tuned single coil probe for a nuclear magnetic resonance spectrometer having improved sensitivity is described comprising a double-tuned circuit means in which the low frequency irradiation is fed to a transmission line through an inductor means. The double-tuned circuit means of the invention may be remotely disposed from the magnetic field which results in greater sensitivity.

  13. 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…

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Dynamic nuclear magnetic resonance field sensing with part-per-trillion resolution.

    PubMed

    Gross, Simon; Barmet, Christoph; Dietrich, Benjamin E; Brunner, David O; Schmid, Thomas; Pruessmann, Klaas P

    2016-12-02

    High-field magnets of up to tens of teslas in strength advance applications in physics, chemistry and the life sciences. However, progress in generating such high fields has not been matched by corresponding advances in magnetic field measurement. Based mostly on nuclear magnetic resonance, dynamic high-field magnetometry is currently limited to resolutions in the nanotesla range. Here we report a concerted approach involving tailored materials, magnetostatics and detection electronics to enhance the resolution of nuclear magnetic resonance sensing by three orders of magnitude. The relative sensitivity thus achieved amounts to 1 part per trillion (10(-12)). To exemplify this capability we demonstrate the direct detection and relaxometry of nuclear polarization and real-time recording of dynamic susceptibility effects related to human heart function. Enhanced high-field magnetometry will generally permit a fresh look at magnetic phenomena that scale with field strength. It also promises to facilitate the development and operation of high-field magnets.

  19. Electron paramagnetic resonance study of the nuclear spin dynamics in an AlAs quantum well

    NASA Astrophysics Data System (ADS)

    Shchepetilnikov, A. V.; Frolov, D. D.; Nefyodov, Yu. A.; Kukushkin, I. V.; Tiemann, L.; Reichl, C.; Dietsche, W.; Wegscheider, W.

    2016-12-01

    The nuclear spin dynamics in an asymmetrically doped 16-nm AlAs quantum well grown along the [001] direction has been studied experimentally using the time decay of the Overhauser shift of paramagnetic resonance of conduction electrons. The nonzero spin polarization of nuclei causing the initial observed Overhauser shift is due the relaxation of the nonequilibrium spin polarization of electrons into the nuclear subsystem near electron paramagnetic resonance owing to the hyperfine interaction. The measured relaxation time of nuclear spins near the unity filling factor is (530 ± 30) min at the temperature T = 0.5 K. This value exceeds the characteristic spin relaxation times of nuclei in GaAs/AlGaAs heterostructures by more than an order of magnitude. This fact indicates the decrease in the strength of the hyperfine interaction in the AlAs quantum well in comparison with GaAs/AlGaAs heterostructures.

  20. Dynamic nuclear magnetic resonance field sensing with part-per-trillion resolution

    NASA Astrophysics Data System (ADS)

    Gross, Simon; Barmet, Christoph; Dietrich, Benjamin E.; Brunner, David O.; Schmid, Thomas; Pruessmann, Klaas P.

    2016-12-01

    High-field magnets of up to tens of teslas in strength advance applications in physics, chemistry and the life sciences. However, progress in generating such high fields has not been matched by corresponding advances in magnetic field measurement. Based mostly on nuclear magnetic resonance, dynamic high-field magnetometry is currently limited to resolutions in the nanotesla range. Here we report a concerted approach involving tailored materials, magnetostatics and detection electronics to enhance the resolution of nuclear magnetic resonance sensing by three orders of magnitude. The relative sensitivity thus achieved amounts to 1 part per trillion (10-12). To exemplify this capability we demonstrate the direct detection and relaxometry of nuclear polarization and real-time recording of dynamic susceptibility effects related to human heart function. Enhanced high-field magnetometry will generally permit a fresh look at magnetic phenomena that scale with field strength. It also promises to facilitate the development and operation of high-field magnets.

  1. Dynamic nuclear magnetic resonance field sensing with part-per-trillion resolution

    PubMed Central

    Gross, Simon; Barmet, Christoph; Dietrich, Benjamin E.; Brunner, David O.; Schmid, Thomas; Pruessmann, Klaas P.

    2016-01-01

    High-field magnets of up to tens of teslas in strength advance applications in physics, chemistry and the life sciences. However, progress in generating such high fields has not been matched by corresponding advances in magnetic field measurement. Based mostly on nuclear magnetic resonance, dynamic high-field magnetometry is currently limited to resolutions in the nanotesla range. Here we report a concerted approach involving tailored materials, magnetostatics and detection electronics to enhance the resolution of nuclear magnetic resonance sensing by three orders of magnitude. The relative sensitivity thus achieved amounts to 1 part per trillion (10−12). To exemplify this capability we demonstrate the direct detection and relaxometry of nuclear polarization and real-time recording of dynamic susceptibility effects related to human heart function. Enhanced high-field magnetometry will generally permit a fresh look at magnetic phenomena that scale with field strength. It also promises to facilitate the development and operation of high-field magnets. PMID:27910860

  2. 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.

  3. 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.

  4. 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.

  5. Nuclear Magnetic Resonance Studies of Tellurium and Antimony Bonding in Crystal Sb2Te3, GeTe, and Ge2Sb2Te5

    NASA Astrophysics Data System (ADS)

    Bobela, David C.; Taylor, P. Craig

    2008-10-01

    As a starting point in understanding the magnetic resonance data for amorphous Ge2Sb2Te5, the prototypical phase change material, we have used 121Sb and 125Te nuclear magnetic resonance (NMR) to study crystalline Sb2Te3, GeTe, and Ge2Sb2Te5. The frequency space data are affected by a quadrupole (121Sb only) and chemical shift (121Sb and 125Te) interaction, which reflect the bonding asymmetries occurring around each nuclei. The 125Te data indicate there are two distinct Te sites in Sb2Te3 and one Te site in the GeTe, in agreement with the known crystal structures. The Ge2Sb2Te5125Te data are less well-resolved, which is probably a consequence of the random arrangement of Sb/Ge atoms around the Te sites. Despite the lack of resolution, these data do correspond to the spectral positions and breadths observed in Sb2Te3 and GeTe, which suggests that Ge2Sb2Te5 contains similar Te bonding structures. The 121Sb data in Sb2Te3 show that the Sb sites have an approximately axially symmetric bonding environment. The Sb data in Ge2Sb2Te5 reveal that the average bonding structure of Sb is very different from the Sb sites occurring in Sb2Te3.

  6. 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.

  7. Carbon-13 nuclear-magnetic-resonance spectroscopy of Forssman hapten.

    PubMed Central

    Koerner, T A; Cary, L W; Li, S C; Li, Y T

    1981-01-01

    The 13C n.m.r. spectrum of Forssman hapten was obtained at 25.16 MHz in [3H] chloroform/[2H] methanol (1:1, v/v), using purified glycosphinogolipid from canine intestinal mucosa (glycolipid I). All amide, olefin, anomeric, intersaccharide glycosidic ether, amide linkage, methyl and many methylene resonances were resolved and assigned. Analysis of the anomeric region reveals the following pentaglycosylceramide structure as originally proposed [Siddiqui & Hakomori (1971) J. Biol. Chem. 246, 5766-5769]: GalNAc (alpha 1 leads to 3) GalNAc (beta 1 leads to 3) Gal (alpha 1 leads to 4) Gal (beta 1 leads to 1) ceramide. Analysis of the amide, olefin and methylene regions reveals no alpha-hydroxy fatty acyl group and less than or equal to 6 mol% unsaturated fatty acyl groups are present. Chemical-shift assignments are reported for the anomeric and glycosidic ether carbon atoms of intersaccharide-linked alpha-galactose and N-acetyl-alpha-galactosamine residues. Two rules are proposed for the assignment of the anomeric form of 1 leads to 3 and 1 leads to 4 linkages of galactose and N-acetylgalactosamine residues present in the glycone of glyco-conjugates. The present study emphasizes the importance of the anomeric "window" (80-120 p.p.m.) in studies of glycone structure. PMID:7316971

  8. 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

  9. 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.

  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. 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.

  12. ϕ meson self-energy in nuclear matter from ϕ N resonant interactions

    NASA Astrophysics Data System (ADS)

    Cabrera, D.; Hiller Blin, A. N.; Vicente Vacas, M. J.

    2017-01-01

    The ϕ -meson properties in cold nuclear matter are investigated by implementing resonant ϕ N interactions as described in effective approaches including the unitarization of scattering amplitudes. Several N*-like states are dynamically generated in these models around 2 GeV, in the vicinity of the ϕ N threshold. We find that both these states and the non-resonant part of the amplitude contribute sizably to the ϕ collisional self-energy at finite nuclear density. These contributions are of a similar strength as the widely studied medium effects from the K ¯K cloud. Depending on model details (position of the resonances and strength of the coupling to ϕ N ) we report a ϕ broadening up to about 40-50 MeV, to be added to the ϕ →K ¯K in-medium decay width, and an attractive optical potential at threshold up to about 35 MeV at normal matter density. The ϕ spectral function develops a double peak structure as a consequence of the mixing of resonance-hole modes with the ϕ quasiparticle peak. The former results point in the direction of making up for missing absorption as reported in ϕ nuclear production experiments.

  13. Studies in protein dynamics using heteronuclear nuclear magnetic resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Vugmeyster, Liliya

    Dynamic processes in proteins are important for their biological function. Several issues in protein dynamics are addressed by applying existing NMR methodologies to investigate dynamics of several small proteins. Amide H/D exchange rates have been measured for the N-terminal domain of the ribosomal protein L9, residues 1--56. The results suggest that the structure of the domain is preserved in isolation and that the stability of the isolated domain is comparable to the stability of this domain in intact L9. Single domain proteins can fold in vitro at rates in excess of 1 x 104 s-1. Measurement of folding rates of this magnitude poses a considerable technical challenge. Off-resonance 15N R1rho measurements are shown to be capable of measuring such fast protein folding rates. The measurements were performed on a sample of the peripheral subunit-binding domain from the dihydrolopoamide acetyltransferase component of the pyruvate dehydrogenase multienzyme complex from Bacillus stearothermophilus 15N labeled at Ala 11. Fast intramolecular motions (on ps-ns time scale) can be studied by heteronuclear laboratory frame NMR relaxation. The temperature dependence of the backbone dynamics of the 36-resiude subdomain of the F-actin bundling protein villin has been investigated by studying the temperature dependence of order parameters obtained from 15N relaxation measurements. The results support the hypothesis that one of the possible mechanisms of thermostability is to lower the heat capacity difference between the folded and unfolded states by lowering the contribution from the backbone dynamics. A commonly used model-free approach for the interpretation of the relaxation data for macromolecules in solution is modified to correct for the decoupling approximation between the overall and internal motions.

  14. Force-detected nuclear magnetic resonance: recent advances and future challenges.

    PubMed

    Poggio, M; Degen, C L

    2010-08-27

    We review recent efforts to detect small numbers of nuclear spins using magnetic resonance force microscopy. Magnetic resonance force microscopy (MRFM) is a scanning probe technique that relies on the mechanical measurement of the weak magnetic force between a microscopic magnet and the magnetic moments in a sample. Spurred by the recent progress in fabricating ultrasensitive force detectors, MRFM has rapidly improved its capability over the last decade. Today it boasts a spin sensitivity that surpasses conventional, inductive nuclear magnetic resonance detectors by about eight orders of magnitude. In this review we touch on the origins of this technique and focus on its recent application to nanoscale nuclear spin ensembles, in particular on the imaging of nanoscale objects with a three-dimensional (3D) spatial resolution better than 10 nm. We consider the experimental advances driving this work and highlight the underlying physical principles and limitations of the method. Finally, we discuss the challenges that must be met in order to advance the technique towards single nuclear spin sensitivity-and perhaps-to 3D microscopy of molecules with atomic resolution.

  15. Mechanical Generation of Radio-Frequency Fields in Nuclear-Magnetic-Resonance Force Microscopy

    NASA Astrophysics Data System (ADS)

    Wagenaar, J. J. T.; den Haan, A. M. J.; Donkersloot, R. J.; Marsman, F.; de Wit, M.; Bossoni, L.; Oosterkamp, T. H.

    2017-02-01

    We present a method for magnetic-resonance force microscopy (MRFM) with ultralow dissipation, by using the higher modes of the mechanical detector as a radio-frequency (rf) source. This method allows MRFM on samples without the need to be close to a conventional electrically driven rf source. Furthermore, since conventional electrically driven rf sources require currents that give dissipation, our method enables nuclear-magnetic-resonance experiments at ultralow temperatures. Removing the need for an on-chip rf source is an important step towards an MRFM which can be widely used in condensed matter physics.

  16. Design and testing of high sensitivity microreceiver coil apparatus for nuclear magnetic resonance and imaging

    NASA Astrophysics Data System (ADS)

    Seeber, D. A.; Cooper, R. L.; Ciobanu, L.; Pennington, C. H.

    2001-04-01

    We report the design and testing of a nuclear magnetic resonance (NMR) microcoil receiver apparatus, employing solenoidal microreceiver coils of dimensions of tens to hundreds of microns, using applied field of 9 T (proton resonance frequency 383 MHz). For the smallest receiver coils we attain sensitivity sufficient to observe proton NMR with signal to noise (S/N) one in a single scan applied to a ˜10 μm3 (10 fl) water sample, containing 7×1011 total proton spins. We also test the dependence of the S/N on important coil parameters, including coil composition and resistivity, turn spacing, and lead lengths.

  17. High frequency electron nuclear double resonance at 239 GHz using a far-infrared laser source

    SciTech Connect

    Paschedag, L.; van Tol, J.; Wyder, P.

    1995-10-01

    We report on the application of {sup 14}N electron nuclear double resonance (ENDOR) at 8.5 T and 239 GHz ({lambda}=1.2 mm) in a {gamma}-irradiated betaine arsenate single crystal. A laser was used as a far-infrared radiation source in a transmission-type electron paramagnetic resonance (EPR) setup without a cavity. The four expected nitrogen ENDOR lines were observed, but due to insufficient saturation of the EPR transitions the signal/noise ratio was not larger than 10 and the signals vanished at temperatures above 20 K. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  18. 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.

  19. 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.

  20. Observation of the 22.5-keV resonance in (149)Sm by the nuclear lighthouse effect.

    PubMed

    Röhlsberger, R; Quast, K W; Toellner, T S; Lee, P L; Sturhahn, W; Alp, E E; Burkel, E

    2001-07-23

    We have observed coherent nuclear resonant scattering of synchrotron radiation at the 22.5-keV resonance of (149)Sm. High-speed rotational sample motion led to an angular deflection of the resonantly scattered radiation off the nonresonant primary beam. This allowed us to determine the resonance energy of the first excited nuclear level of (149)Sm to be 22496(4) eV. Because of the angular deflection of the resonant photons, time spectra of coherent nuclear resonant scattering can be recorded as a function of a spatial coordinate. Time resolutions of a few 10 ps can be expected, which are beyond the limits of existing x-ray detection schemes.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Application of nuclear magnetic resonance spectroscopy for identification of ciprofloxacin crystalluria.

    PubMed

    Morell-Garcia, Daniel; Barceló, Bernardino; Rodriguez, Adrian; Liñeiro, Victor; Robles, Rosa; Vidal-Puigserver, Joan; Costa-Bauzá, Antonia; Grases, Felix

    2015-01-01

    This is a report describing a previously healthy young patient, who experienced crystalluria and non-cholestatic acute liver injury after a single intravenous dose of 400mg. The nuclear magnetic resonance spectra confirmed that the urinary sediment in our patient was formed by pure ciprofloxacin. The nuclear magnetic resonance spectra ((1)H NMR) of the urine sediment are a good test to confirm the composition of the crystals observed by electron microscopy and infrared spectrum. The findings indicate the importance of adequate hydration, urinalysis, measurement of pH and liver enzyme levels, prior to treatment with ciprofloxacin. Our findings also indicate that ciprofloxacin should not be administered to patients with renal tubular acidosis, due to their high urinary pH.

  7. 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.

  8. Quantitative nuclear magnetic resonance spectroscopic determination of the oxyethylene group content of polysorbates.

    PubMed

    Sugimoto, Naoki; Koike, Ryo; Furusho, Noriko; Tanno, Makoto; Yomota, Chikako; Sato, Kyoko; Yamazaki, Takeshi; Tanamoto, Kenichi

    2007-08-01

    Guidelines for the oxyethylene group (EO) content of polysorbates are set by the Food and Agriculture Organization/World Health Organization Joint Expert Committee on Food Additives. However, the classical titration method for EO determination is difficult and time-consuming. Here, we show that quantitative (1)H-nuclear magnetic resonance spectroscopy can determine the EO contents of polysorbates rapidly and simply. The EO signals were identified through comparisons with sorbitan monolaurate and poly(ethylene glycol) distearate. Potassium hydrogen phthalate was used as an internal standard. The EO contents were estimated from the ratio of the signal intensities of EO to the internal standard. Two nuclear magnetic resonance systems were used to validate the proposed method. The EO content of commercial polysorbates 20, 60, 65, and 80 was determined to be within the recommended limits using this technique. Our approach thus represents an additional or alternative method of determining the EO contents of polysorbates.

  9. 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.

  10. 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.

  11. Measurement of conductivity and permittivity on samples sealed in nuclear magnetic resonance tubes

    SciTech Connect

    Huang, W.; Angell, C. A.; Yarger, J. L.; Richert, R.

    2013-07-15

    We present a broadband impedance spectroscopy instrument designed to measure conductivity and/or permittivity for samples that are sealed in glass tubes, such as the standard 5 mm tubes used for nuclear magnetic resonance experiments. The calibrations and corrections required to extract the dielectric properties of the sample itself are outlined. It is demonstrated that good estimates of the value of dc-conductivity can be obtained even without correcting for the effects of glass or air on the overall impedance. The approach is validated by comparing data obtained from samples sealed in nuclear magnetic resonance tubes with those from standard dielectric cells, using glycerol and butylmethylimidazolium-hexafluorophosphate as respective examples of a molecular and an ionic liquid. This instrument and approach may prove useful for other studies of permittivity and conductivity where contact to the metal electrodes or to the ambient atmosphere needs to be avoided.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. Nuclear magnetic resonance in sedimentary rocks: Effect of proton desorption rate

    NASA Astrophysics Data System (ADS)

    Mendelson, Kenneth S.

    1982-09-01

    In a discussion of nuclear magnetic resonance of protons in the pore fluid of sedimentary rocks, Cohen and Mendelson assumed that the desorption rate of protons from the rock surface is much faster than the relaxation rate of the magnetization for protons on the surface. In the present paper it is shown that this assumption is not necessary and conditions are established under which the analysis of Cohen and Mendelson is valid.

  17. A noninvasive method to study regulation of extracellular fluid volume in rats using nuclear magnetic resonance

    EPA Pesticide Factsheets

    NMR fluid measurements of commonly used rat strains when subjected to SQ normotonic or hypertonic salines, as well as physiologic comparisons to sedentary and exercised subjects.This dataset is associated with the following publication:Gordon , C., P. Phillips , and A. Johnstone. A Noninvasive Method to Study Regulation of Extracellular Fluid Volume in Rats Using Nuclear Magnetic Resonance. American Journal of Physiology- Renal Physiology. American Physiological Society, Bethesda, MD, USA, 310(5): 426-31, (2016).

  18. 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.

  19. 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.

  20. Solid state nuclear magnetic resonance studies of prion peptides and proteins

    SciTech Connect

    Heller, Jonathan

    1997-08-01

    High-resolution structural studies using x-ray diffraction and solution nuclear magnetic resonance (NMR) are not feasible for proteins of low volubility and high tendency to aggregate. Solid state NMR (SSNMR) is in principle capable of providing structural information in such systems, however to do this efficiently and accurately, further SSNMR tools must be developed This dissertation describes the development of three new methods and their application to a biological system of interest, the priori protein (PrP).

  1. 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.

  2. 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.

  3. Proton nuclear magnetic resonance of intact friend leukemia cells: phosphorylcholine increase during differentiation

    SciTech Connect

    Agris, P.F.; Campbell, I.D.

    1982-06-18

    Proton nuclear magnetic resonance of intact Friend leukemia cells was used to analyze their erythroid-like differentiation. The technique, which requires only 10/sup 8/ to 10/sup 9/ cells and approximately 2 minutes for acquisition of each spectrum, demonstrated the occurrence of many signal changes during differentiation. With cell extracts, 64 signals were assigned to 12 amino acids and 19 other intermediary metabolites, and a dramatic signal change was attributed to a fourfrease in cytoplasmic phosphorylcholines.

  4. 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.

  5. Nuclear magnetic resonance monitoring of treatment and prediction of outcome in multiple sclerosis.

    PubMed Central

    Miller, D H; Thompson, A J

    1999-01-01

    Magnetic resonance (MR) techniques provide an objective, sensitive and quantitative assessment of the evolving pathology in multiple sclerosis. There is an increasing definition of the pathological specificity of newer techniques, and more robust correlations with clinical evolution are emerging. As the pathophysiological basis of in vivo nuclear MR signal abnormalities is further elucidated, it is likely that the importance of MR as a tool to monitor new therapies will increase. PMID:10603620

  6. A practical guide for nuclear resonance vibrational spectroscopy (NRVS) of biochemical samples and model compounds.

    PubMed

    Wang, Hongxin; Alp, Esen Ercan; Yoda, Yoshitaka; Cramer, Stephen P

    2014-01-01

    Nuclear resonance vibrational spectroscopy (NRVS) has been used by physicists for many years. However, it is still a relatively new technique for bioinorganic users. This technique yields a vibrational spectrum for a specific element, which can be easily interpreted. Furthermore, isotopic labeling allows for site-specific experiments. In this chapter, we discuss how to access specific beamlines, what kind of equipment is used in NRVS, and how the sample should be prepared and the data collected and analyzed.

  7. Development and applications of NMR (nuclear magnetic resonance) in low fields and zero field

    SciTech Connect

    Bielecki, A.

    1987-05-01

    This dissertation is about nuclear magnetic resonance (NMR) spectroscopy in the absence of applied magnetic fields. NMR is usually done in large magnetic fields, often as large as can be practically attained. The motivation for going the opposite way, toward zero field, is that for certain types of materials, particularly powdered or polycrystalline solids, the NMR spectra in zero field are easier to interpret than those obtained in high field. 92 refs., 60 figs., 1 tab.

  8. Noncyclic geometric quantum computation in a nuclear-magnetic-resonance system

    SciTech Connect

    Wang, Z. S.; Liu, G. Q.; Ji, Y. H.

    2009-05-15

    A scheme is proposed to include both cyclic and noncyclic geometric quantum computations in nuclear-magnetic-resonance system by the invariant theory. By controlling magnetic field and arbitrary parameters in the invariant operator, the phases accumulated in the entangling quantum gates for single- and two-qubit systems are pure geometric phases. Thus, fault tolerance may occur in some critical magnetic field parameters for either cyclic or noncyclic evolution by differently choosing for gate time.

  9. 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.

  10. 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

    2013-08-05

    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.

  11. 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.

  12. 13C Nuclear magnetic resonance studies to the binding of isocyanides to various hemoglobins and myoglobins.

    PubMed

    Dill, K; Satterlee, J D; Richards, J H

    1978-10-03

    Interactions between ethyl and isopropyl isocyanides and various hemoglobins and myoglobins have been studied by 13C nuclear magnetic resonance. The results indicate that the chemical shift of the bound isocyanide depends on the structure of the hemoglobin subunit or myoglobin. The resonances exhibited by isocyanides bound to myoglobin are sensitive to pH in contrast to the situation with rabbit and human hemoglobins. beta subunits of opossum, rabbit, and human hemoglobins show a significantly greater preferential affinity for CO relative to EIC than do alpha subunits which have allowed the assignment of resonances. Rabbit, human, and opossum hemoglobin subunits bind ethyl isocyanide without observable preferences and an excess of DPG does not appear to affect this random order of ligation. In contrast, an excess of IHP seems to cause preferential ligation of the alpha subunits in these hemoglobins. The results have been used to gain insights into the differing characteristics of the ligand binding pockets of these various hemoglobins.

  13. Evidence for nuclear Landau-Zener effect: New resonance mechanism in heavy-ion reactions

    SciTech Connect

    Abe, Y.; Park, J.Y.

    1983-12-01

    Characteristic resonancelike peaks recently observed in the angle-integrated inelastic cross sections for the /sup 13/C-/sup 17/O system are understood in terms of the Landau-Zener excitation mechanism at energy level crossings. Angle-integrated inelastic cross sections estimated with the Landau-Zener formula show a series of resonancelike peaks as a function of incident energy, each of which is associated with a grazing angular momentum of the relative motion between nuclei. Simple expressions are given for resonance energies and ''widths'' of new ''resonances.'' This resonance mechanism is a new one, which has not been known in nuclear reactions nor in atomic collisions, although it is based on the well-known Landau-Zener promotion mechanism.

  14. Resonance Region Nuclear Data Analysis to Support Advanced Fuel Cycle Development

    SciTech Connect

    Dunn, Michael E; Derrien, Herve; Leal, Luiz C; Gil, Choong-Sup; Kim, D.

    2011-01-01

    The Oak Ridge National Laboratory (ORNL) and the Korean Atomic Energy Research Institute (KAERI) are performing collaborative research as part of a three-year United States (U.S.) / Republic of Korea (ROK) International Nuclear Energy Research Initiative (I-NERI) project to provide improved neutron cross-section data with uncertainty or covariance data important for advanced fuel cycle and nuclear safeguards applications. ORNL and KAERI have initiated efforts to prepare new cross-section evaluations for 240Pu, 237Np, and the stable Cm isotopes. At the current stage of the I-NERI project, ORNL has recently completed a preliminary resonance-region cross-section evaluation with covariance data for 240Pu and initiated resonance evaluation efforts for 237Np and 244Cm. Likewise, KAERI is performing corresponding high-energy cross-section analyses (i.e., above the resonance region) for the noted isotopes. The paper provides results pertaining to the new resonance region evaluation efforts with emphasis on the new 240Pu evaluation.

  15. 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

  16. 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.

  17. 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

  18. Description of nuclear octupole and quadrupole deformation close to axial symmetry: Octupole vibrations in the X(5) nuclei Nd150 and Sm152

    NASA Astrophysics Data System (ADS)

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

    2010-03-01

    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 Nd150 and Sm152 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Screening nucleotide binding to amino acid-coated supports by surface plasmon resonance and nuclear magnetic resonance.

    PubMed

    Cruz, Carla; Cabrita, Eurico J; Queiroz, João A

    2011-08-01

    Here, we describe a rapid and efficient screening method using surface plasmon resonance (SPR) and saturation transfer difference-nuclear magnetic resonance (STD-NMR) spectroscopy to yield information regarding the residues involved in nucleotide binding to amino acid-coated supports. The aim of this work was to explore the use of these spectroscopic techniques to study amino acid-nucleotide interactions in order to improve the binding specificity of the amino acid ligands used to purify plasmid DNA. For SPR, we present a strategy that immobilizes arginine and lysine on a surface as model supports, and we analyze binding responses when synthetic homo-deoxyoligonucleotides are injected over the amino acid surface. The binding responses are detectable and reproducible despite the small size of the immobilized amino acids. Using STD-NMR, we performed epitope mapping of homo-deoxyoligonucleotides bound to L-arginine-bisoxyran-Sepharose and L-lysine-Sepharose supports. Polynucleotide binding preferences differed; for example, polyC interacted preferentially through its backbone with the two supports, whereas polyT bound the supports through its thymine moiety. STD-NMR combined with SPR measurements was successfully used to screen amino acid-nucleotide interactions and determine the binding affinities of the complexes.

  4. [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.

  5. 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

  6. [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.

  7. Fermi resonance in CO2: Mode assignment and quantum nuclear effects from first principles molecular dynamics.

    PubMed

    Basire, Marie; Mouhat, Félix; Fraux, Guillaume; Bordage, Amélie; Hazemann, Jean-Louis; Louvel, Marion; Spezia, Riccardo; Bonella, Sara; Vuilleumier, Rodolphe

    2017-04-07

    Vibrational spectroscopy is a fundamental tool to investigate local atomic arrangements and the effect of the environment, provided that the spectral features can be correctly assigned. This can be challenging in experiments and simulations when double peaks are present because they can have different origins. Fermi dyads are a common class of such doublets, stemming from the resonance of the fundamental excitation of a mode with the overtone of another. We present a new, efficient approach to unambiguously characterize Fermi resonances in density functional theory (DFT) based simulations of condensed phase systems. With it, the spectral features can be assigned and the two resonating modes identified. We also show how data from DFT simulations employing classical nuclear dynamics can be post-processed and combined with a perturbative quantum treatment at a finite temperature to include analytically thermal quantum nuclear effects. The inclusion of these effects is crucial to correct some of the qualitative failures of the Newtonian dynamics simulations at a low temperature such as, in particular, the behavior of the frequency splitting of the Fermi dyad. We show, by comparing with experimental data for the paradigmatic case of supercritical CO2, that these thermal quantum effects can be substantial even at ambient conditions and that our scheme provides an accurate and computationally convenient approach to account for them.

  8. 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.

  9. Quantum Computing Using Pulse-Based Electron-Nuclear Double Resonance (endor):. Molecular Spin-Qubits

    NASA Astrophysics Data System (ADS)

    Sato, Kazuo; Nakazawa, Shigeki; Rahimi, Robabeh D.; Nishida, Shinsuke; Ise, Tomoaki; Shimoi, Daisuke; Toyota, Kazuo; Morita, Yasushi; Kitagawa, Masahiro; Carl, Parick; Höfner, Peter; Takui, Takeji

    2009-06-01

    Electrons with the spin quantum number 1/2, as physical qubits, have naturally been anticipated for implementing quantum computing and information processing (QC/QIP). Recently, electron spin-qubit systems in organic molecular frames have emerged as a hybrid spin-qubit system along with a nuclear spin-1/2 qubit. Among promising candidates for QC/QIP from the materials science side, the reasons for why electron spin-qubits such as molecular spin systems, i.e., unpaired electron spins in molecular frames, have potentialities for serving for QC/QIP will be given in the lecture (Chapter), emphasizing what their advantages or disadvantages are entertained and what technical and intrinsic issues should be dealt with for the implementation of molecular-spin quantum computers in terms of currently available spin manipulation technology such as pulse-based electron-nuclear double resonance (pulsed or pulse ENDOR) devoted to QC/QIP. Firstly, a general introduction and introductory remarks to pulsed ENDOR spectroscopy as electron-nuclear spin manipulation technology is given. Super dense coding (SDC) experiments by the use of pulsed ENDOR are also introduced to understand differentiating QC ENDOR from QC NMR based on modern nuclear spin technology. Direct observation of the spinor inherent in an electron spin, detected for the first time, will be shown in connection with the entanglement of an electron-nuclear hybrid system. Novel microwave spin manipulation technology enabling us to deal with genuine electron-electron spin-qubit systems in the molecular frame will be introduced, illustrating, from the synthetic strategy of matter spin-qubits, a key-role of the molecular design of g-tensor/hyperfine-(A-)tensor molecular engineering for QC/QIP. Finally, important technological achievements of recently-emerging CD ELDOR (Coherent-Dual ELectron-electron DOuble Resonance) spin technology enabling us to manipulate electron spin-qubits are described.

  10. 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

  11. 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.

  12. Dynamic nuclear spin polarization in the resonant laser excitation of an InGaAs quantum dot.

    PubMed

    Högele, A; Kroner, M; Latta, C; Claassen, M; Carusotto, I; Bulutay, C; Imamoglu, A

    2012-05-11

    Resonant optical excitation of lowest-energy excitonic transitions in self-assembled quantum dots leads to nuclear spin polarization that is qualitatively different from the well-known optical orientation phenomena. By carrying out a comprehensive set of experiments, we demonstrate that nuclear spin polarization manifests itself in quantum dots subjected to finite external magnetic field as locking of the higher energy Zeeman transition to the driving laser field, as well as the avoidance of the resonance condition for the lower energy Zeeman branch. We interpret our findings on the basis of dynamic nuclear spin polarization originating from noncollinear hyperfine interaction and find excellent agreement between experiment and theory. Our results provide evidence for the significance of noncollinear hyperfine processes not only for nuclear spin diffusion and decay, but also for buildup dynamics of nuclear spin polarization in a coupled electron-nuclear spin system.

  13. 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

  14. Periodic ab initio calculation of nuclear quadrupole parameters as an assignment tool in solid-state NMR spectroscopy: applications to 23Na NMR spectra of crystalline materials.

    PubMed

    Johnson, Clive; Moore, Elaine A; Mortimer, Michael

    2005-05-01

    Periodic ab initio HF calculations using the CRYSTAL code have been used to calculate (23)Na NMR quadrupole parameters for a wide range of crystalline sodium compounds including Na(3)OCl. An approach is developed that can be used routinely as an alternative to point-charge modelling schemes for the assignment of distinct lines in (23)Na NMR spectra to specific crystallographic sodium sites. The calculations are based on standard 3-21 G and 6-21 G molecular basis sets and in each case the same modified basis set for sodium is used for all compounds. The general approach is extendable to other quadrupolar nuclei. For the 3-21 G calculations a 1:1 linear correlation between experimental and calculated values of C(Q)((23)Na) is obtained. The 6-21 G calculations, including the addition of d-polarisation functions, give better accuracy in the calculation of eta((23)Na). The sensitivity of eta((23)Na) to hydrogen atom location is shown to be useful in testing the reported hydrogen-bonded structure of Na(2)HPO(4).

  15. Revised rates for the stellar triple-α process from measurement of 12C nuclear resonances

    NASA Astrophysics Data System (ADS)

    Fynbo, Hans O. U.; Diget, Christian Aa.; Bergmann, Uffe C.; Borge, Maria J. G.; Cederkäll, Joakim; Dendooven, Peter; Fraile, Luis M.; Franchoo, Serge; Fedosseev, Valentin N.; Fulton, Brian R.; Huang, Wenxue; Huikari, Jussi; Jeppesen, Henrik B.; Jokinen, Ari S.; Jones, Peter; Jonson, Björn; Köster, Ulli; Langanke, Karlheinz; Meister, Mikael; Nilsson, Thomas; Nyman, Göran; Prezado, Yolanda; Riisager, Karsten; Rinta-Antila, Sami; Tengblad, Olof; Turrion, Manuela; Wang, Youbao; Weissman, Leonid; Wilhelmsen, Katarina; Äystö, Juha; ISOLDE Collaboration

    2005-01-01

    In the centres of stars where the temperature is high enough, three α-particles (helium nuclei) are able to combine to form 12C because of a resonant reaction leading to a nuclear excited state. (Stars with masses greater than ~0.5 times that of the Sun will at some point in their lives have a central temperature high enough for this reaction to proceed.) Although the reaction rate is of critical significance for determining elemental abundances in the Universe, and for determining the size of the iron core of a star just before it goes supernova, it has hitherto been insufficiently determined. Here we report a measurement of the inverse process, where a 12C nucleus decays to three α-particles. We find a dominant resonance at an energy of ~11MeV, but do not confirm the presence of a resonance at 9.1MeV (ref. 3). We show that interference between two resonances has important effects on our measured spectrum. Using these data, we calculate the triple-α rate for temperatures from 107K to 1010K and find significant deviations from the standard rates. Our rate below ~5 × 107K is higher than the previous standard, implying that the critical amounts of carbon that catalysed hydrogen burning in the first stars are produced twice as fast as previously believed. At temperatures above 109K, our rate is much less, which modifies predicted nucleosynthesis in supernovae.

  16. Measurements for spin inversion and noninversion in successive decays via nuclear magnetic resonance on oriented nuclei

    SciTech Connect

    Ohya, S.; Ohtsubo, T.; Komatsuzaki, K.; Cho, D.J.; Muto, S.

    1996-09-01

    Nuclear magnetic resonance on oriented nuclei (NMR-ON) measurements were performed on the successive decays of {sup 89}Zr-{sup 89}Y{sup {ital m}} and {sup 191}Os-{sup 191}Ir{sup {ital m}} in Fe. The NMR-ON spectra of {sup 89}Zr{ital Fe} and {sup 191}Os{ital Fe} were obtained by detecting {gamma} rays from the decay of the isomers, {sup 89}Y{sup m} and {sup 191}Ir{sup m}, respectively. For {sup 89}Zr{ital Fe}, the anisotropy of the {gamma} ray increased at the resonance. On the other hand, for {sup 191}Os{ital Fe} the anisotropy of the {gamma} ray decreased at the resonance. These phenomena were explained using the spin inversion and spin noninversion processes including the lifetimes of the isomers and spin lattice relaxation times. NMR-ON measurements for such spin inversion and noninversion processes were reported. The resonance spectra were also observed by detecting {beta} rays from {sup 89}Zr and {sup 191}Os. In these experiments the magnetic moments of {sup 89}Zr and {sup 191}Os were determined to be {minus}1.08 (2) {mu}{sub N} and 0.962 (28) {mu}{sub N}, respectively. The signs of the magnetic moments of {sup 89}Y{sup m} and {sup 191}Ir{sup m} were also determined to be positive. {copyright} {ital 1996 The American Physical Society.}

  17. Nuclear magnetic resonance study of the crystallization kinetics in soft magnetic nanocrystalline materials

    NASA Astrophysics Data System (ADS)

    Barbatti, C. F.; Sinnecker, E. H. C. P.; Sarthour, R. S.; Guimarães, A. P.

    2002-05-01

    We used the nuclear magnetic resonance technique to study the evolution of the structural and magnetic properties of Fe-based melt-spun ribbons of Fe73.5Cu1Nb3Si13.5B9, Fe73.5Cu1Nb3Si18.5B4, and Fe86Zr7Cu1B6, as-cast and annealed at 500, 540, and 430 °C, respectively. Experiments were carried out at 4.2 K and zero-applied magnetic field, and in a controlled radio-frequency (rf) field. This type of measurement allows us to observe B and Nb sites, and makes it possible to distinguish signals associated with regions of different magnetic hardnesses. The results exhibit a high dependence of the spectra on rf power. For Fe-Si-based alloys, we observe well-defined 93Nb resonance signals from three distinct sites according to the concentration of Fe atoms in their neighborhood. In the Fe73.5Cu1Nb3Si18.5B4 spectra we also observe a peak around 34 MHz, connected to the 11B resonance in different Fe-B compounds, which remains as the rf power decreases, suggesting that the signals come from atoms inside a soft magnetic region. As for the Fe-Zr alloy, we also observe a peak around 36 MHz, identified as the 11B resonance, and a broad line around 62 MHz.

  18. Nuclear magnetic resonance studies of intracellular ions in perfused from heart

    SciTech Connect

    Burnstein, D.; Fossel, E.T.

    1987-06-01

    Intracellular sodium, potassium, and lithium were observed in a perfused frog heart by nuclear magnetic resonance (NMR) spectroscopy. A perfusate buffer containing the shift reagent, dysprosium tripolyphosphate, was used in combination with mathematical filtering or presaturation of the extracellular resonance to separate the intra- and extracellular sodium NMR signals. Addition of 10 ..mu..M ouabain to the perfusate, perfusion with a zero potassium, low-calcium buffer, and replacement of 66% of the perfusate sodium with lithium resulted in changes in the intracellular sodium levels. An increase of 45% in the intracellular sodium was observed when changing the pacing rate from 0 to 60 beats/min (with proportional changes for intermediate pacing rates). The ratio of intracellular potassium to sodium concentration was determined to be 2.3 by NMR, indicating that a substantial amount of the intracellular potassium is undetectable with these NMR method. In addition, intracellular lithium was observed during perfusion with a lithium-containing perfusate.

  19. Chirality-sensitive nuclear magnetic resonance effects induced by indirect spin-spin coupling

    NASA Astrophysics Data System (ADS)

    Garbacz, P.; Buckingham, A. D.

    2016-11-01

    It is predicted that, for two spin-1/2 nuclei coupled by indirect spin-spin coupling in a chiral molecule, chirality-sensitive induced electric polarization can be observed at the frequencies equal to the sum and difference between the spin resonance frequencies. Also, an electric field oscillating at the difference frequency can induce spin coherences which allow the direct discrimination between enantiomers by nuclear magnetic resonance. The dominant contribution to the magnitude of these expected chiral effects is proportional to the permanent electric dipole moment and to the antisymmetric part of the indirect spin-spin coupling tensor of the chiral molecule. Promising compounds for experimental tests of the predictions are derivatives of 1,3-difluorocyclopropene.

  20. Chirality-sensitive nuclear magnetic resonance effects induced by indirect spin-spin coupling.

    PubMed

    Garbacz, P; Buckingham, A D

    2016-11-28

    It is predicted that, for two spin-1/2 nuclei coupled by indirect spin-spin coupling in a chiral molecule, chirality-sensitive induced electric polarization can be observed at the frequencies equal to the sum and difference between the spin resonance frequencies. Also, an electric field oscillating at the difference frequency can induce spin coherences which allow the direct discrimination between enantiomers by nuclear magnetic resonance. The dominant contribution to the magnitude of these expected chiral effects is proportional to the permanent electric dipole moment and to the antisymmetric part of the indirect spin-spin coupling tensor of the chiral molecule. Promising compounds for experimental tests of the predictions are derivatives of 1,3-difluorocyclopropene.

  1. 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.

  2. 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.

  3. 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

    2015-04-07

    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.

  4. 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.

  5. Nuclear magnetic resonance in cancer, XII: Application of NMR malignancy index to human lung tumours.

    PubMed Central

    Goldsmith, M.; Koutcher, J. A.; Damadian, R.

    1977-01-01

    Sixty specimens of human lung tissue from 52 individuals were inspected at 22.5 MHz by proton magnetic resonance techniques. The purpose of the study was to evaluate the diagnostic capabilities of the nuclear magnetic resonance (NMR) technique for the diagnosis of malignancy. The combination of two NMR parameters (spin-lattice (T1) and spin-spin (T2) relaxation times) into a malignancy index yielded 3 cases of overlap between the two populations of tissue. The mean and standard deviations obtained were 1.966 +/- 0.262 for normal tissue, and 2.925 +/- 0.864 for malignant specimens. In addition, analysis of the electrolyte and water content of the tissues confirm that factors other than specimen water content influence the relaxation time. PMID:911662

  6. 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.

  7. 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.

  8. Nuclear resonant inelastic X-ray scattering at high pressure and low temperature

    PubMed Central

    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

    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 technical 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. PMID:25931094

  9. Nuclear resonant inelastic X-ray scattering at high pressure and low temperature

    DOE PAGES

    Bi, Wenli; Zhao, Jiyong; Lin, Jung -Fu; ...

    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

  10. Nuclear resonant inelastic X-ray scattering at high pressure and low temperature.

    PubMed

    Bi, Wenli; Zhao, Jiyong; Lin, Jung-Fu; Jia, Quanjie; Hu, Michael Y; Jin, Changqing; Ferry, Richard; Yang, Wenge; Struzhkin, Viktor; Alp, E Ercan

    2015-05-01

    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 technical development is given. The Fe-specific phonon density of states and magnetism from the Fe sublattice in Eu(57)Fe2As2 at high pressure and low temperature were derived by using this new capability.

  11. Nuclear fragmentation and charge-exchange reactions induced by pions in the Δ -resonance region

    NASA Astrophysics Data System (ADS)

    Feng, Zhao-Qing

    2016-11-01

    The dynamics of the nuclear fragmentations and the charge exchange reactions in pion-nucleus collisions near the Δ (1232) resonance energies has been investigated within the Lanzhou quantum molecular dynamics transport model. An isospin-, momentum-, and density-dependent pion-nucleon potential is implemented in the model, which influences the pion dynamics, in particular the kinetic energy spectra, but weakly impacts the fragmentation mechanism. The absorption process in pion-nucleon collisions to form the Δ (1232) resonance dominates the heating mechanism of the target nucleus. The excitation energy transferred to the target nucleus increases with the pion kinetic energy and is similar for both π-- and π+-induced reactions. The magnitude of fragmentation of the target nucleus weakly depends on the pion energy. The isospin ratio in the pion double-charge exchange is influenced by the isospin ingredient of target nucleus.

  12. High-resolution proton nuclear magnetic resonance spectroscopy of ovarian cyst fluid.

    PubMed

    Boss, E A; Moolenaar, S H; Massuger, L F; Boonstra, H; Engelke, U F; de Jong, J G; Wevers, R A

    2000-08-01

    Most ovarian tumors are cystic structures containing variable amounts of fluid. Several studies of ovarian cyst fluid focus on one specific metabolite using conventional assay systems. We examined the potential of (1)H-nuclear magnetic resonance spectroscopy in evaluation of the overall metabolic composition of cyst fluid from different ovarian tumors. Ovarian cyst fluid samples obtained from 40 patients with a primary ovarian tumor (12 malignant and 28 benign) were examined. After deproteinization and pD standardization, we performed (1)H-NMR spectroscopy on a 600 MHz instrument. With (1)H-NMR spectroscopy we found detectable concentrations of 36 metabolites with high intersample variation. A number of unassigned resonances as well as unexpected metabolites were found. We introduce an overall inventory of the low-molecular-weight metabolites in ovarian cyst fluid with corresponding resonances. Significant differences in concentration (p < 0.01) were found for several metabolites (including an unknown metabolite) between malignant and benign ovarian cysts. Furthermore, higher concentrations in malignant- and lower in benign fluids were found compared to normal serum values, indicating local cyst wall metabolic processes in case of malignant transformation. We conclude that (1)H-nuclear magnetic resonance spectroscopy can give an overview of low-molecular-weight proton-containing metabolities present in ovarian cyst fluid samples. The metabolic composition of cyst fluid differs significantly between benign and malignant ovarian tumors. Furthermore, differences between benign subgroups possibly related to histopathological behaviour can be detected. The presence of N-acetyl aspartic acid and 5-oxoproline exclusively in serous cystadenoma samples is remarkable. Future studies will concentrate on these findings and explore the possibilities of extrapolating information from the in vitro studies to in vivo practice, in which metabolic differences between malignant and

  13. 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.

  14. Prospects for sub-micron solid state nuclear magnetic resonance imaging with low-temperature dynamic nuclear polarization.

    PubMed

    Thurber, Kent R; Tycko, Robert

    2010-06-14

    We evaluate the feasibility of (1)H 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 microL sample yields a (1)H 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 (1)H NMR signals from 1 microm(3) voxel volumes should be readily detectable, and voxels as small as 0.03 microm(3) may eventually be detectable. Through homonuclear decoupling with a frequency-switched Lee-Goldburg spin echo technique, we obtain 830 Hz (1)H 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.

  15. Experimental study of quantum simulation for quantum chemistry with a nuclear magnetic resonance simulator.

    PubMed

    Lu, Dawei; Xu, Nanyang; Xu, Boruo; Li, Zhaokai; Chen, Hongwei; Peng, Xinhua; Xu, Ruixue; Du, Jiangfeng

    2012-10-13

    Quantum computers have been proved to be able to mimic quantum systems efficiently in polynomial time. Quantum chemistry problems, such as static molecular energy calculations and dynamical chemical reaction simulations, become very intractable on classical computers with scaling up of the system. Therefore, quantum simulation is a feasible and effective approach to tackle quantum chemistry problems. Proof-of-principle experiments have been implemented on the calculation of the hydrogen molecular energies and one-dimensional chemical isomerization reaction dynamics using nuclear magnetic resonance systems. We conclude that quantum simulation will surpass classical computers for quantum chemistry in the near future.

  16. Exact two-component relativistic theory for nuclear magnetic resonance parameters.

    PubMed

    Sun, Qiming; Liu, Wenjian; Xiao, Yunlong; Cheng, Lan

    2009-08-28

    An exact two-component (X2C) relativistic theory for nuclear magnetic resonance parameters is obtained by first a single block-diagonalization of the matrix representation of the Dirac operator in a magnetic-field-dependent basis and then a magnetic perturbation expansion of the resultant two-component Hamiltonian and transformation matrices. Such a matrix formulation is not only simple but also general in the sense that the various ways of incorporating the field dependence can be treated in a unified manner. The X2C dia- and paramagnetic terms agree individually with the corresponding four-component ones up to machine accuracy for any basis.

  17. Realization of quantum state privacy amplification in a nuclear magnetic resonance quantum system

    NASA Astrophysics Data System (ADS)

    Hao, Liang; Wang, Chuan; Long, Gui Lu

    2010-06-01

    Quantum state privacy amplification (QSPA) is the quantum analogue of classical privacy amplification. If the state information of a series of single-particle states has some leakage, QSPA reduces this leakage by condensing the state information of two particles into the state of one particle. Recursive applications of the operations will eliminate the quantum state information leakage to a required minimum level. In this paper, we report the experimental implementation of a quantum state privacy amplification protocol in a nuclear magnetic resonance system. The density matrices of the states are constructed in the experiment, and the experimental results agree well with theory.

  18. 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.

  19. Micro-coil detection of nuclear magnetic resonance for nanofluidic samples

    NASA Astrophysics Data System (ADS)

    Shibahara, A.; Casey, A.; Lusher, C. P.; Saunders, J.; Aßmann, C.; Schurig, Th.; Drung, D.

    2014-02-01

    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 3He in the gas phase at 4.2 K in a 30 mT magnetic field.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Chemical characterization of pigment gallstones using /sup 13/C nuclear magnetic resonance analysis

    SciTech Connect

    Woolfenden, W.R.; Grant, D.M.; Straight, R.C.; Englert, E. Jr.

    1982-07-30

    The unique ability of Carbon-13 nuclear magnetic resonance analysis with cross polarization/magic angle spinning techniques to investigate chemical structures of solids is used to probe the chemical characteristics of several gallstone types. New pulse program techniques are used to distinguish various carbon atoms in studying the polymeric nature of the black bilirubinoid pigment of pigment gallstones. Evidence for the involvement of the carboxyl group and noninvolvement of vinyl groups of bilirubinoids in the polymeric bond formation is presented. Conjugated bilirubin structures are found to be present in some solid residues from pigment stones extracted with acidic methanol/chloroform.

  5. 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.

  6. 31P nuclear magnetic resonance study of the proton-irradiated KTiOPO4

    NASA Astrophysics Data System (ADS)

    Kim, Se-Hun; Lee, Cheol Eui

    2013-08-01

    31P nuclear magnetic resonance (NMR) was employed to study the effects of proton irradiation on KTiOPO4 (KTP) in view of the previously studied paramagnetic impurity doping effects. High-resolution 31P NMR measurements showed significant increase in the isotropic chemical shifts of the two inequivalent phosphorus sites in the proton-irradiated KTP system, indicating decrease in the electron density around the phosphorous nuclei. The 31P NMR linewidths of the KTP system manifested anomalies associated with the superionic transition and with the polaron formation, which became much weaker after proton irradiation. Besides, the activation energy of the charge carriers increased significantly after proton irradiation.

  7. New Approach to High-Pressure Nuclear Magnetic Resonance with Anvil Cells

    NASA Astrophysics Data System (ADS)

    Meissner, T.; Goh, S. K.; Haase, J.; Meier, B.; Rybicki, D.; Alireza, P. L.

    2010-04-01

    A novel approach that uses radio-frequency microcoils in the high-pressure region of anvil cells with Nuclear Magnetic Resonance (NMR) experiments is described. High-sensitivity Al NMR data at 70 kbar for Al metal are presented for the first time. An expected decrease in the Al Knight shift at 70 kbar is observed, as well as an unexpected change in the local charge symmetry at the Al nucleus. The latter is not predicted by chemical structure analysis under high pressure.

  8. 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.

  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. 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.

  11. 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.

  12. Recent advances in computational methods for nuclear magnetic resonance data processing.

    PubMed

    Gao, Xin

    2013-02-01

    Although three-dimensional protein structure determination using nuclear magnetic resonance (NMR) spectroscopy is a computationally costly and tedious process that would benefit from advanced computational techniques, it has not garnered much research attention from specialists in bioinformatics and computational biology. In this paper, we review recent advances in computational methods for NMR protein structure determination. We summarize the advantages of and bottlenecks in the existing methods and outline some open problems in the field. We also discuss current trends in NMR technology development and suggest directions for research on future computational methods for NMR.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Defect-induced magnetism in SiC probed by nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Zhang, Z. T.; Dmytriieva, D.; Molatta, S.; Wosnitza, J.; Wang, Yutian; Helm, M.; Zhou, Shengqiang; Kühne, H.

    2017-02-01

    We give evidence for intrinsic defect-induced bulk paramagnetism in SiC by means of 13C and 29Si nuclear magnetic resonance (NMR) spectroscopy. The temperature dependence of the internal dipole-field distribution, probed by the spin part of the NMR Knight shift and the spectral linewidth, follows the Curie law and scales very well with the macroscopic dc susceptibility. In order to quantitatively analyze the NMR spectra, a microscopic model based on dipole-dipole interactions was developed. The very good agreement between these simulations and the NMR data establishes a direct relation between the frequency distribution of the spectral intensity and the corresponding real-space volumes of nuclear spins. The presented approach by NMR can be applied to a variety of similar materials and, thus, opens a new avenue for the microscopic exploration and exploitation of diluted bulk magnetism in semiconductors.

  18. The potential of nuclear magnetic resonance to track lipids in planta.

    PubMed

    Munz, Eberhard; Jakob, Peter M; Borisjuk, Ljudmilla

    2016-11-01

    Nuclear Magnetic Resonance (NMR) provides a highly flexible platform for non invasive analysis and imaging biological samples, since the manipulation of nuclear spin allows the tailoring of experiments to maximize the informativeness of the data. MRI is capable of visualizing a holistic picture of the lipid storage in living plant/seed. This review has sought to explain how the technology can be used to acquire functional and physiological data from plant samples, and how to exploit it to characterize lipid deposition in vivo. At the same time, we have referred to the current limitations of NMR technology as applied to plants, and in particular of the difficulty of transferring methodologies optimized for animal/medical subjects to plant ones. A forward look into likely developments in the field is included, anticipating its key future role in the study of living plant.

  19. Transmission Nuclear Resonance Fluorescence Measurements of 238U in Thick Targets

    SciTech Connect

    Quiter, Brian J.; Ludewigt, Bernhard A.; Mozin, Vladimir V.; Wilson, Cody; Korbly, Steve

    2010-08-31

    Transmission nuclear resonance fluorescence measurements were made on targets consisting of Pb and depleted U with total areal densities near 86 g/cm2. The 238U content n the targets varied from 0 to 8.5percent (atom fraction). The experiment demonstrates the capability of using transmission measurements as a non-destructive technique to identify and quantify the presence of an isotope in samples with thicknesses comparable to he average thickness of a nuclear fuel assembly. The experimental data also appear to demonstrate the process of notch refilling with a predictable intensity. Comparison of measured spectra to previous backscatter 238U measurements indicates general agreement in observed excited states. Two new 238U excited states and possibly a third state have also been observed.

  20. Investigation of resonances in 20Mg: Implications for astrophysics and nuclear forces

    NASA Astrophysics Data System (ADS)

    Randhawa, Jaspreet; Kanungo, Rituparna; Alcorta, Martin; Burbadge, Christina; Burke, Devin; Christian, Greg; Davids, Barry; Even, Julia; Hackman, Greg; Henderson, Jack; Ishimoto, Shigeru; Kaur, Satbir; Keefe, Matthew; Kruecken, Reiner; Lighthall, Jon; Moukaddam, Mohamad; Padilla-Rodal, Elizabeth; Smith, Jenna; Turko, Joseph; Workman, Orry

    2016-09-01

    18Ne(2p, γ)20Mg provides a possible pathway for breakout from the hot CNO cycles to the rp-process in type I X-ray bursts. This reaction rate is uncertain due to lack of any experimental information on the resonant states in 20Mg above proton emission threshold. Recent calculations using nuclear forces from chiral perturbation theory predict quite a different level structure for 20Mg with and without inclusion of three nucleon forces. These differences make study of 20Mg states important to constraint both nuclear theory and this reaction rate. We have investigated the excited states in 20Mg through inelastic deuteron scattering. The experiment was performed using the IRIS facility at TRIUMF, Canada. The 20Mg beam with an average intensity of 500 pps and energy of 8.5A MeV was directed at novel thin windowless solid deuteron target. Experiment and initial observations will be discussed.

  1. 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

  2. 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

  3. Nuclear magnetic resonance of external protons using continuous dynamical decoupling with shallow NV centers

    NASA Astrophysics Data System (ADS)

    de Las Casas, Charles; Ohno, Kenichi; Awschalom, David D.

    2015-03-01

    The nitrogen vacancy (NV) center in diamond is a paramagnetic defect with excellent spin properties that can reside within a few nanometers of the diamond surface, enabling atomic-scale magnetic resonance sensing of external nuclear spins. Here we use rotating frame longitudinal spin relaxation (T1ρ) based sensing schemes, known as Continuous Dynamical Decoupling (CDD), to detect external nuclear spins with shallow NV centers (<5 nm from the surface). Distinguishing neighboring nuclear spins from each other requires the NV center be near enough to create differences in the hyperfine shifts and coupling strengths of the nuclei. However, spin coherence time and consequently the sensitivity of dynamical decoupling techniques degrade sharply as NVs become shallower. We use strong continuous driving to overcome this fast decoherence and detect an ensemble of external nuclear spins using a single shallow NV center with a short T2 (<2 μs) at magnetic fields as high as 0.5 Tesla. The increased sensitivity of this method relative to pulsed dynamical decoupling techniques demonstrates the benefits of CDD for sensing with very shallow NV centers. This work was supported by DARPA, AFOSR, and the DIAMANT program.

  4. 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.

  5. 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.

  6. 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.

  7. Field-induced spin reorientation in [Fe/Cr ] n multilayers studied by nuclear resonance reflectivity

    NASA Astrophysics Data System (ADS)

    Andreeva, M.; Gupta, A.; Sharma, G.; Kamali, S.; Okada, K.; Yoda, Y.

    2015-10-01

    We present depth-resolved nuclear resonance reflectivity studies of the magnetization evolution in [57Fe(3nm ) /Cr (1.2 nm ) ] 10 multilayer under applied external field. The measurements have been performed at the station BL09XU of SPring-8 at different values of the external field (0-1500 Oe). We apply the joint fit of the delayed reflectivity curves and the time spectra of the nuclear resonance reflectivity measured at different grazing angles for enhancement of the depth resolution and reliability of results. We show that the azimuth angle, which is used in all papers devoted to the magnetization profile determination, has a more complicated physical sense due to the partially coherent averaging of the scattering amplitudes from magnetic lateral domains. We describe how to select the true azimuth angle from the determined "effective azimuth angle." Finally we obtain the noncollinear twisted magnetization depth profiles where the spin-flop state appears sequentially in different 57Fe layers at increasing applied field.

  8. 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

  9. Remote sensing of sample temperatures in nuclear magnetic resonance using photoluminescence of semiconductor quantum dots.

    PubMed

    Tycko, Robert

    2014-07-01

    Knowledge of sample temperatures during nuclear magnetic resonance (NMR) measurements is important for acquisition of optimal NMR data and proper interpretation of the data. Sample temperatures can be difficult to measure accurately for a variety of reasons, especially because it is generally not possible to make direct contact to the NMR sample during the measurements. Here I show that sample temperatures during magic-angle spinning (MAS) NMR measurements can be determined from temperature-dependent photoluminescence signals of semiconductor quantum dots that are deposited in a thin film on the outer surface of the MAS rotor, using a simple optical fiber-based setup to excite and collect photoluminescence. The accuracy and precision of such temperature measurements can be better than ±5K over a temperature range that extends from approximately 50K (-223°C) to well above 310K (37°C). Importantly, quantum dot photoluminescence can be monitored continuously while NMR measurements are in progress. While this technique is likely to be particularly valuable in low-temperature MAS NMR experiments, including experiments involving dynamic nuclear polarization, it may also be useful in high-temperature MAS NMR and other forms of magnetic resonance.

  10. Remote sensing of sample temperatures in nuclear magnetic resonance using photoluminescence of semiconductor quantum dots

    PubMed Central

    Tycko, Robert

    2014-01-01

    Knowledge of sample temperatures during nuclear magnetic resonance (NMR) measurements is important for acquisition of optimal NMR data and proper interpretation of the data. Sample temperatures can be difficult to measure accurately for a variety of reasons, especially because it is generally not possible to make direct contact to the NMR sample during the measurements. Here I show that sample temperatures during magic-angle spinning (MAS) NMR measurements can be determined from temperature-dependent photoluminescence signals of semiconductor quantum dots that are deposited in a thin film on the outer surface of the MAS rotor, using a simple optical fiber-based setup to excite and collect photoluminescence. The accuracy and precision of such temperature measurements can be better than ±5 K over a temperature range that extends from approximately 50 K (−223° C) to well above 310 K (37° C). Importantly, quantum dot photoluminescence can be monitored continuously while NMR measurements are in progress. While this technique is likely to be particularly valuable in low-temperature MAS NMR experiments, including experiments involving dynamic nuclear polarization, it may also be useful in high-temperature MAS NMR and other forms of magnetic resonance. PMID:24859817

  11. Towards a beyond 1 GHz solid-state nuclear magnetic resonance: External lock operation in an external current mode for a 500 MHz nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Takahashi, Masato; Ebisawa, Yusuke; Tennmei, Konosuke; Yanagisawa, Yoshinori; Hosono, Masami; Takasugi, Kenji; Hase, Takashi; Miyazaki, Takayoshi; Fujito, Teruaki; Nakagome, Hideki; Kiyoshi, Tsukasa; Yamazaki, Toshio; Maeda, Hideaki

    2012-10-01

    Achieving a higher magnetic field is important for solid-state nuclear magnetic resonance (NMR). But a conventional low temperature superconducting (LTS) magnet cannot exceed 1 GHz (23.5 T) due to the critical magnetic field. Thus, we started a project to replace the Nb3Sn innermost coil of an existing 920 MHz NMR (21.6 T) with a Bi-2223 high temperature superconducting (HTS) innermost coil. Unfortunately, the HTS magnet cannot be operated in persistent current mode; an external dc power supply is required to operate the NMR magnet, causing magnetic field fluctuations. These fluctuations can be stabilized by a field-frequency lock system based on an external NMR detection coil. We demonstrate here such a field-frequency lock system in a 500 MHz LTS NMR magnet operated in an external current mode. The system uses a 7Li sample in a microcoil as external NMR detection system. The required field compensation is calculated from the frequency of the FID as measured with a frequency counter. The system detects the FID signal, determining the FID frequency, and calculates the required compensation coil current to stabilize the sample magnetic field. The magnetic field was stabilized at 0.05 ppm/3 h for magnetic field fluctuations of around 10 ppm. This method is especially effective for a magnet with large magnetic field fluctuations. The magnetic field of the compensation coil is relatively inhomogeneous in these cases and the inhomogeneity of the compensation coil can be taken into account.

  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. Proton nuclear magnetic resonance and spectrophotometric studies of nickel(II)-iron(II) hybrid hemoglobins

    SciTech Connect

    Shibayama, N.; Inubushi, T.; Morimoto, H.; Yonetani, T.

    1987-04-21

    Ni(II)-Fe(II) hybrid hemoglobins, ..cap alpha..(Fe)/sub 2/..beta..(Ni)/sub 2/ and ..cap alpha..(Ni)/sub 2/..beta..(Fe)/sub 2/, have been characterized by proton nuclear magnetic resonance with Ni(II) protoporphyrin IX (Ni-PP) incorporated in apoprotein, which serves as a permanent deoxyheme. ..cap alpha..(Fe)/sub 2/..beta..(Ni)/sub 2/, ..cap alpha..(Ni)/sub 2/..beta..(Fe)/sub 2/, and NiHb commonly show exchangeable proton resonances at 11 and 14 ppm, due to hydrogen-bonded protons in a deoxy-like structure. Upon binding of carbon monoxide (CO) to ..cap alpha..(Fe)/sub 2/..beta..(Ni)/sub 2/, these resonances disappear at pH 6.5 to pH 8.5. On the other hand, the complementary hybrid ..cap alpha..(Ni)/sub 2/..beta..(Fe-CO)/sub 2/ showed the 11 and 14 ppm resonances at low pH. Upon raising pH, the intensities of both resonances are reduced, although these changes are not synchronized. Electronic absorption spectra and hyperfine-shifted proton resonances indicate that the ligation of CO in the ..beta..(Fe) subunits induced changes in the coordination and spin states of Ni-PP in the ..cap alpha.. subunits. In a deoxy-like structure, the coordination of Ni-PP in the ..cap alpha.. subunits is predominantly in a low-spin (S = 0) four-coordination state, whereas in an oxy-like structure the contribution of a high-spin (S = 1) five-coordination state markedly increased. Ni-PP in the ..beta.. subunits always takes a high-spin five-coordination state regardless of solution conditions and the state of ligation in the partner ..cap alpha..(Fe) subunits. In the ..beta..(Ni) subunits, a significant downfield shift of the proximal histidyl N/sub delta/H resonance and a change in the absorption spectrum of Ni-PP were detected, upon changing the quaternary structure of the hybrid. The chemical shifts were analyzed in terms of the E11-Val methyls vs. the porphyrin rings in hybrid Hbs.

  14. Self-association of cromolyn sodium in aqueous solution characterized by nuclear magnetic resonance spectroscopy.

    PubMed

    Ding, Xuan; Stringfellow, Thomas C; Robinson, Joseph R

    2004-05-01

    The major objective of this study was to investigate and characterize the solution properties of cromolyn sodium (in D(2)O or D(2)O/H(2)O phosphate buffer at pH 7.5) using nuclear magnetic resonance (NMR) spectroscopy. The self-association of cromolyn molecules was examined primarily via one-dimensional (1)H and (13)C, and two-dimensional homonuclear NOESY NMR. Significant spectral shifts were observed for a majority of cromolyn (1)H and (13)C resonances, and are attributed to inter-molecular ring-stacking association accompanied by intra-molecular conformational changes. The critical self-association concentration was determined to be 10 mg/mL at pH 7.5 and 25 degrees C by measuring the chemical shift of a specific cromolyn (1)H resonance. The observed magnitude and sign changes of NOESY correlations indicate the formation of cromolyn aggregates with restricted molecular mobility. Mesomorphic liquid crystal formation is suggested by uniformly pronounced line broadening in concentrated cromolyn solutions; the transition concentration was approximately 60 mg/mL at 25 degrees C, which is consistent with literature findings based on other techniques. A stronger tendency toward association was observed at lower temperature but aggregation appeared to be independent of pH. Lastly, it was concluded that self-association of cromolyn is promoted by the presence of monovalent cations as a result of reduced electrostatic repulsive forces.

  15. Cardiovascular imaging in the diagnosis and monitoring of cardiotoxicity: cardiovascular magnetic resonance and nuclear cardiology.

    PubMed

    Pepe, Alessia; Pizzino, Fausto; Gargiulo, Paola; Perrone-Filardi, Pasquale; Cadeddu, Christian; Mele, Donato; Monte, Ines; Novo, Giuseppina; Zito, Concetta; Di Bella, Gianluca

    2016-05-01

    Chemotherapy-induced cardiotoxicity (CTX) is a determining factor for the quality of life and mortality of patients administered potentially cardiotoxic drugs and in long-term cancer survivors. Therefore, prevention and early detection of CTX are highly desirable, as is the exploration of alternative therapeutic strategies and/or the proposal of potentially cardioprotective treatments. In recent years, cardiovascular imaging has acquired a pivotal role in this setting. Although echocardiography remains the diagnostic method most used to monitor cancer patients, the need for more reliable, reproducible and accurate detection of early chemotherapy-induced CTX has encouraged the introduction of second-line advanced imaging modalities, such as cardiac magnetic resonance (CMR) and nuclear techniques, into the clinical setting. This review of the Working Group on Drug Cardiotoxicity and Cardioprotection of the Italian Society of Cardiology aims to afford an overview of the most important findings from the literature about the role of CMR and nuclear techniques in the management of chemotherapy-treated patients, describe conventional and new parameters for detecting CTX from both diagnostic and prognostic perspectives and provide integrated insight into the role of CMR and nuclear techniques compared with other imaging tools and versus the positions of the most important international societies.

  16. Nuclear, optical, and magnetic resonance imaging in a mouse mammary window chamber model

    NASA Astrophysics Data System (ADS)

    Leung, Hui Min; Schafer, Rachel; Gmitro, Arthur F.

    2014-09-01

    An orthotopic mouse mammary window chamber (MWC) model has been developed for multimodal in-vivo functional and anatomical imaging of breast cancer xenografts. Capabilities to image numerous physiological aspects of the same tumor microenvironment over time has important applications such as in experiments studying the efficacies of therapeutic interventions, improvement of cancer detection and investigating basic cancer biology. The compatibility of this MWC model with optical, nuclear and magnetic resonance imaging (MRI) makes it possible to perform a multitude of studies ranging from cellular imaging to whole body imaging. Thus, the MWC represents a powerful tool for breast cancer research. Here, two imaging applications are highlighted, namely the nuclear imaging of glycolytic metabolism with 18FFDG and MRI of tissue perfusion. Nuclear imaging is performed with the use of a 3μm thin phosphor scintillator placed directly in contact with the tissue and visible light from the scintillation is directly detected in a low noise, light tight imaging system. Tissue perfusion is imaged either qualitatively with a dynamic contrast enhancement (DCE) MRI technique or quantitatively with an arterial spin labeling flow-sensitive alternating inversion recovery-rapid acquisition with relaxation enhancement (FAIR-RARE) technique.

  17. Excitation of the {sup 229m}Th nuclear isomer via resonance conversion in ionized atoms

    SciTech Connect

    Karpeshin, F. F.; Trzhaskovskaya, M. B.

    2015-09-15

    Pressing problems concerning the optical pumping of the 7.6-eV {sup 229m}Th nuclear isomer, which is a candidate for a new nuclear optical reference point for frequencies, are examined. Physics behind the mechanism of the two-photon optical pumping of the isomer is considered. It is shown that, irrespective of the pumping scheme, a dominant contribution comes, in accord with what was proven earlier for the 3.5-eV isomer, from the resonance 8s–7s transition. Details of an optimum experimental scheme are discussed. It is shown that, after isomer excitation, the atom involved remains with a high probability in an excited state at an energy of about 0.5 eV rather than in the ground state, the required energy of the two photons being equal to the energy of the nuclear level plus the energy of the lowest 7s state of the atom. The estimated pumping time is about 1.5 s in the case where the field strength of each laser is 1 V/cm.

  18. Leading-order relativistic effects on nuclear magnetic resonance shielding tensors.

    PubMed

    Manninen, Pekka; Ruud, Kenneth; Lantto, Perttu; Vaara, Juha

    2005-03-15

    We present perturbational ab initio calculations of the nuclear-spin-dependent relativistic corrections to the nuclear magnetic resonance shielding tensors that constitute, together with the other relativistic terms reported by us earlier, the full leading-order perturbational set of results for the one-electron relativistic contributions to this observable, based on the (Breit-)Pauli Hamiltonian. These contributions are considered for the H(2)X (X = O,S,Se,Te,Po) and HX (X = F,Cl,Br,I,At) molecules, as well as the noble gas (Ne, Ar, Kr, Xe, Rn) atoms. The corrections are evaluated using the relativistic and magnetic operators as perturbations on an equal footing, calculated using analytical linear and quadratic response theory applied on top of a nonrelativistic reference state provided by self-consistent field calculations. The (1)H and heavy-atom nuclear magnetic shielding tensors are compared with four component, nearly basis-set-limit Dirac-Hartree-Fock calculations that include positronic excitations, as well as available literature data. Besides the easy interpretability of the different contributions in terms of familiar nonrelativistic concepts, the accuracy of the present perturbational scheme is striking for the isotropic part of the shielding tensor, for systems including elements up to Xe.

  19. 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.

  20. Angstrom-Resolution Magnetic Resonance Imaging of Single Molecules via Wave-Function Fingerprints of Nuclear Spins

    NASA Astrophysics Data System (ADS)

    Ma, Wen-Long; Liu, Ren-Bao

    2016-08-01

    Single-molecule sensitivity of nuclear magnetic resonance (NMR) and angstrom resolution of magnetic resonance imaging (MRI) are the highest challenges in magnetic microscopy. Recent development in dynamical-decoupling- (DD) enhanced diamond quantum sensing has enabled single-nucleus NMR and nanoscale NMR. Similar to conventional NMR and MRI, current DD-based quantum sensing utilizes the "frequency fingerprints" of target nuclear spins. The frequency fingerprints by their nature cannot resolve different nuclear spins that have the same noise frequency or differentiate different types of correlations in nuclear-spin clusters, which limit the resolution of single-molecule MRI. Here we show that this limitation can be overcome by using "wave-function fingerprints" of target nuclear spins, which is much more sensitive than the frequency fingerprints to the weak hyperfine interaction between the targets and a sensor under resonant DD control. We demonstrate a scheme of angstrom-resolution MRI that is capable of counting and individually localizing single nuclear spins of the same frequency and characterizing the correlations in nuclear-spin clusters. A nitrogen-vacancy-center spin sensor near a diamond surface, provided that the coherence time is improved by surface engineering in the near future, may be employed to determine with angstrom resolution the positions and conformation of single molecules that are isotope labeled. The scheme in this work offers an approach to breaking the resolution limit set by the "frequency gradients" in conventional MRI and to reaching the angstrom-scale resolution.

  1. Normal mode analysis of Pyrococcus furiosus rubredoxin via nuclear resonance vibrational spectroscopy (NRVS) and resonance raman spectroscopy.

    PubMed

    Xiao, Yuming; Wang, Hongxin; George, Simon J; Smith, Matt C; Adams, Michael W W; Jenney, Francis E; Sturhahn, Wolfgang; Alp, Ercan E; Zhao, Jiyong; Yoda, Y; Dey, Abishek; Solomon, Edward I; Cramer, Stephen P

    2005-10-26

    We have used (57)Fe nuclear resonance vibrational spectroscopy (NRVS) to study the Fe(S(cys))(4) site in reduced and oxidized rubredoxin (Rd) from Pyrococcus furiosus (Pf). The oxidized form has also been investigated by resonance Raman spectroscopy. In the oxidized Rd NRVS, strong asymmetric Fe-S stretching modes are observed between 355 and 375 cm(-1); upon reduction these modes shift to 300-320 cm(-1). This is the first observation of Fe-S stretching modes in a reduced Rd. The peak in S-Fe-S bend mode intensity is at approximately 150 cm(-1) for the oxidized protein and only slightly lower in the reduced case. A third band occurs near 70 cm(-1) for both samples; this is assigned primarily as a collective motion of entire cysteine residues with respect to the central Fe. The (57)Fe partial vibrational density of states (PVDOS) were interpreted by normal mode analysis with optimization of Urey-Bradley force fields. The three main bands were qualitatively reproduced using a D(2)(d) Fe(SC)(4) model. A C(1) Fe(SCC)(4) model based on crystallographic coordinates was then used to simulate the splitting of the asymmetric stretching band into at least 3 components. Finally, a model employing complete cysteines and 2 additional neighboring atoms was used to reproduce the detailed structure of the PVDOS in the Fe-S stretch region. These results confirm the delocalization of the dynamic properties of the redox-active Fe site. Depending on the molecular model employed, the force constant K(Fe-S) for Fe-S stretching modes ranged from 1.24 to 1.32 mdyn/A. K(Fe-S) is clearly diminished in reduced Rd; values from approximately 0.89 to 1.00 mdyn/A were derived from different models. In contrast, in the final models the force constants for S-Fe-S bending motion, H(S-Fe-S), were 0.18 mdyn/A for oxidized Rd and 0.15 mdyn/A for reduced Rd. The NRVS technique demonstrates great promise for the observation and quantitative interpretation of the dynamical properties of Fe-S proteins.

  2. Structure, spectra and antioxidant action of ascorbic acid studied by density functional theory, Raman spectroscopic and nuclear magnetic resonance techniques

    NASA Astrophysics Data System (ADS)

    Singh, Gurpreet; Mohanty, B. P.; Saini, G. S. S.

    2016-02-01

    Structure, vibrational and nuclear magnetic resonance spectra, and antioxidant action of ascorbic acid towards hydroxyl radicals have been studied computationally and in vitro by ultraviolet-visible, nuclear magnetic resonance and vibrational spectroscopic techniques. Time dependant density functional theory calculations have been employed to specify various electronic transitions in ultraviolet-visible spectra. Observed chemical shifts and vibrational bands in nuclear magnetic resonance and vibrational spectra, respectively have been assigned with the help of calculations. Changes in the structure of ascorbic acid in aqueous phase have been examined computationally and experimentally by recording Raman spectra in aqueous medium. Theoretical calculations of the interaction between ascorbic acid molecule and hydroxyl radical predicted the formation of dehydroascorbic acid as first product, which has been confirmed by comparing its simulated spectra with the corresponding spectra of ascorbic acid in presence of hydrogen peroxide.

  3. Structure, spectra and antioxidant action of ascorbic acid studied by density functional theory, Raman spectroscopic and nuclear magnetic resonance techniques.

    PubMed

    Singh, Gurpreet; Mohanty, B P; Saini, G S S

    2016-02-15

    Structure, vibrational and nuclear magnetic resonance spectra, and antioxidant action of ascorbic acid towards hydroxyl radicals have been studied computationally and in vitro by ultraviolet-visible, nuclear magnetic resonance and vibrational spectroscopic techniques. Time dependant density functional theory calculations have been employed to specify various electronic transitions in ultraviolet-visible spectra. Observed chemical shifts and vibrational bands in nuclear magnetic resonance and vibrational spectra, respectively have been assigned with the help of calculations. Changes in the structure of ascorbic acid in aqueous phase have been examined computationally and experimentally by recording Raman spectra in aqueous medium. Theoretical calculations of the interaction between ascorbic acid molecule and hydroxyl radical predicted the formation of dehydroascorbic acid as first product, which has been confirmed by comparing its simulated spectra with the corresponding spectra of ascorbic acid in presence of hydrogen peroxide.

  4. MQXFS1 Quadrupole Design Report

    SciTech Connect

    Ambrosio, Giorgio

    2016-04-14

    This report presents the reference design of MQXFS1, the first 1.5 m prototype of the low-beta quadrupoles (MQXF) for the LHC High Luminosity Upgrade. The MQXF quadrupoles have 150 mm aperture, coil peak field of about 12 T, and use $Nb_{3}Sn$ conductor. The design is based on the LARP HQ quadrupoles, which had 120 mm aperture. MQXFS1 has 1st generation cable cross-section and magnetic design.

  5. 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.

  6. 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.

  7. Time-Domain Nuclear Magnetic Resonance Investigation of Water Dynamics in Different Ginger Cultivars.

    PubMed

    Huang, Chongyang; Zhou, Qi; Gao, Shan; Bao, Qingjia; Chen, Fang; Liu, Chaoyang

    2016-01-20

    Different ginger cultivars may contain different nutritional and medicinal values. In this study, a time-domain nuclear magnetic resonance method was employed to study water dynamics in different ginger cultivars. Significant differences in transverse relaxation time T2 values assigned to the distribution of water in different parts of the plant were observed between Henan ginger and four other ginger cultivars. Ion concentration and metabolic analysis showed similar differences in Mn ion concentrations and organic solutes among the different ginger cultivars, respectively. On the basis of Pearson's correlation analysis, many organic solutes and 6-gingerol, the main active substance of ginger, exhibited significant correlations with water distribution as determined by NMR T2 relaxation, suggesting that the organic solute differences may impact water distribution. Our work demonstrates that low-field NMR relaxometry provides useful information about water dynamics in different ginger cultivars as affected by the presence of different organic solutes.

  8. Nuclear magnetic resonance spectroscopic analysis of homoallylic and bis homoallylic substituted methyl fatty ester derivatives.

    PubMed

    Jie, M S; Cheng, K L

    1995-02-01

    Using a combination of selective irradiation 1H nuclear magnetic resonance experiments and two-dimensional 1H-13C correlation spectroscopy spectral analysis of homoallylic and bis homoallylic substituted (azido, acetoxy, chloro and oxo) fatty ester derivatives, the carbon shifts of the ethylenic carbon atoms were determined. In the case of methyl 12-azido-9Z-octadecenoate (homoallylic), the carbon chemical shifts of the ethylenic C-9 and C-10 carbon nuclei are 133.092 and 124.596 ppm, respectively. In methyl 9-azido-12Z-octadecenoate (bis homoallylic), the carbon chemical shift of the ethylenic C-12 and C-13 carbon nuclei are 128.118 and 131.243 ppm, respectively.

  9. Sampling the structure and chemical order in assemblies of ferromagnetic nanoparticles by nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Liu, Yuefeng; Luo, Jingjie; Shin, Yooleemi; Moldovan, Simona; Ersen, Ovidiu; Hébraud, Anne; Schlatter, Guy; Pham-Huu, Cuong; Meny, Christian

    2016-05-01

    Assemblies of nanoparticles are studied in many research fields from physics to medicine. However, as it is often difficult to produce mono-dispersed particles, investigating the key parameters enhancing their efficiency is blurred by wide size distributions. Indeed, near-field methods analyse a part of the sample that might not be representative of the full size distribution and macroscopic methods give average information including all particle sizes. Here, we introduce temperature differential ferromagnetic nuclear resonance spectra that allow sampling the crystallographic structure, the chemical composition and the chemical order of non-interacting ferromagnetic nanoparticles for specific size ranges within their size distribution. The method is applied to cobalt nanoparticles for catalysis and allows extracting the size effect from the crystallographic structure effect on their catalytic activity. It also allows sampling of the chemical composition and chemical order within the size distribution of alloyed nanoparticles and can thus be useful in many research fields.

  10. Sampling the structure and chemical order in assemblies of ferromagnetic nanoparticles by nuclear magnetic resonance

    PubMed Central

    Liu, Yuefeng; Luo, Jingjie; Shin, Yooleemi; Moldovan, Simona; Ersen, Ovidiu; Hébraud, Anne; Schlatter, Guy; Pham-Huu, Cuong; Meny, Christian

    2016-01-01

    Assemblies of nanoparticles are studied in many research fields from physics to medicine. However, as it is often difficult to produce mono-dispersed particles, investigating the key parameters enhancing their efficiency is blurred by wide size distributions. Indeed, near-field methods analyse a part of the sample that might not be representative of the full size distribution and macroscopic methods give average information including all particle sizes. Here, we introduce temperature differential ferromagnetic nuclear resonance spectra that allow sampling the crystallographic structure, the chemical composition and the chemical order of non-interacting ferromagnetic nanoparticles for specific size ranges within their size distribution. The method is applied to cobalt nanoparticles for catalysis and allows extracting the size effect from the crystallographic structure effect on their catalytic activity. It also allows sampling of the chemical composition and chemical order within the size distribution of alloyed nanoparticles and can thus be useful in many research fields. PMID:27156575

  11. Nuclear magnetic resonance studies of xenon clusters in zeolite NaA

    NASA Astrophysics Data System (ADS)

    Jameson, Cynthia J.; Jameson, A. Keith; Gerald, Rex, II; de Dios, Angel C.

    1992-02-01

    We have observed the equilibrium distribution of Xe atoms trapped in the alpha cages of zeolite NaA at 300 and at 360 K for low to high xenon loadings. The experimental distributions obtained by nuclear magnetic resonance (NMR) spectroscopy differ from two previously proposed statistical distributions. The experimental deviations from these statistical models can be explained by the attractive Xe-Xe interactions which favor clustering at low to medium loading, and the higher energies associated with the overcrowded cage disfavoring clusters of eight Xe atoms at high loadings. The temperature dependence of the 129Xe NMR chemical shift of each cluster has been measured in the range 188-421 K, except that for Xe8, which was determined only up to 300 K. The observed shifts and their temperature dependence are interpreted by using the results of ab initio calculations of the intermolecular shielding function in the 39Ar system as a model for the 129Xe system.

  12. Nuclear Magnetic Resonance Identification of New Sulfonic Acid Metabolites of Chloroacetanilide Herbicides

    USGS Publications Warehouse

    Morton, M.D.; Walters, F.H.; Aga, D.S.; Thurman, E.M.; Larive, C.K.

    1997-01-01

    The detection of the sulfonic acid metabolites of the chloroacetanilide herbicides acetochlor, alachlor, butachlor, propachlor, and, more recently, metolachlor in surface and ground water suggests that a common mechanism for dechlorination exists via the glutathione conjugation pathway. The identification of these herbicides and their metabolites is important due to growing public awareness and concern about pesticide levels in drinking water. Although these herbicides are regulated, little is known about the fate of their metabolites in soil. The sulfonic acid metabolites were synthesized by reaction of the parent compounds with an excess of sodium sulfite. Acetochlor, alachlor, butachlor, metolachlor, and propachlor and their sulfonic acid metabolites were studied by nuclear magnetic resonance spectroscopy and fast atom bombardment mass spectrometry. This paper provides a direct method for the preparation and characterization of these compounds that will be useful in the analysis and study of chloracetanilide herbicides and their metabolites.

  13. Solid state nuclear magnetic resonance studies of cross polarization from quadrupolar nuclei

    SciTech Connect

    De Paul, Susan M.

    1997-08-01

    The development of solid-state Nuclear Magnetic Resonance (NMR) has, to a large extent, focused on using spin-1/2 nuclei as probes to investigate molecular structure and dynamics. For such nuclei, the technique of cross polarization is well-established as a method for sensitivity enhancement. However, over two-thirds of the nuclei in the periodic table have a spin-quantum number greater than one-half and are known as quadrupolar nuclei. Such nuclei are fundamental constituents of many inorganic materials including minerals, zeolites, glasses, and gels. It is, therefore, of interest to explore the extent to which polarization can be transferred from quadrupolar nuclei. In this dissertation, solid-state NMR experiments involving cross polarization from quadrupolar nuclei to spin-1/2 nuclei under magic-angle spinning (MAS) conditions are investigated in detail.

  14. Some notes on data analysis for nuclear resonant inelastic x-ray scattering

    NASA Astrophysics Data System (ADS)

    Hu, Michael Y.

    2016-12-01

    Nuclear Resonant Inelastic X-ray Scattering (NRIXS) is a spectroscopy method to study atomic vibrations and dynamics, currently done with synchrotron radiation at a few high energy third generation facilities. It finds a wide range of applications in condensed matter physics, materials science, chemistry, biophysics, geosciences, and high-pressure researches. Many atomic dynamics and lattice thermodynamics information can be derived from NRIXS measurements. Phonon Density of States (DOS) characterizes lattice dynamics of a material and can be derived under the quasi-harmonic approximation. Combined with modeling and simulations, results from NRIXS can provide unique and clarifying insights into many fields of research. As for a spectroscopic technique, in order to be able to provide reliable information, close attention should be paid to many issues during experiments and data analysis afterwards. Here we discuss several issues relevant to its data analysis, namely, those of multiple sites, background treatments, and error estimates for some derived quantities.

  15. Tracking thermal degradation on passion fruit juice through Nuclear Magnetic Resonance and chemometrics.

    PubMed

    Soares, Marcia Valeria L; Alves Filho, Elenilson G; Silva, Lorena Mara A; Novotny, Etelvino Henrique; Canuto, Kirley Marques; Wurlitzer, Nedio Jair; Narain, Narendra; de Brito, Edy Sousa

    2017-03-15

    Thermal food processing mainly aims to control microorganism in order to extend its shelf life. However, it may induce chemical and nutritional changes in foodstuff. The Nuclear Magnetic Resonance (NMR) coupled to multivariate analysis was used to evaluate the effect of different thermal processing conditions (85 and 140°C for 4; 15; 30; and 60s) on the passion fruit juice using an Armfield pasteurizer. Through this approach it was possible to identify the changes in the juice composition. The temperature and the time lead to a hydrolysis of the sucrose to glucose and fructose. Additionally, juice submitted to 140°C for 60s results in the degradation of the sucrose and the formation of 5-(hydroxymethyl)-2-furfural (HMF). Despite no novel chemical marker has been identified, the (1)H NMR chemometrics approach may contribute in the choice of the temperature and time to be employed in the juice processing.

  16. Molecular Structure of Aggregated Amyloid-β: Insights from Solid State Nuclear Magnetic Resonance

    PubMed Central

    Tycko, Robert

    2016-01-01

    Amyloid-β (Aβ) peptides aggregate to form polymorphic amyloid fibrils and a variety of intermediate assemblies, including oligomers and protofibrils, both in vitro and in human brain tissue. Since the beginning of the 21st century, considerable progress has been made on characterization of the molecular structures of Aβ aggregates. Full molecular structural models that are based primarily on data from solid state nuclear magnetic resonance measurements have been developed for several in vitro Aβ fibrils and one metastable protofibril. Partial structural characterization of other aggregation intermediates has been achieved. One full structural model for fibrils derived from brain tissue has also been reported. Future work is likely to focus on additional structures from brain tissue and on further clarification of nonfibrillar Aβ aggregates. PMID:27481836

  17. Nuclear magnetic resonance (NMR) imaging of Arnold-Chiari type I malformation with hydromyelia

    SciTech Connect

    DeLaPaz, R.L.; Brady, T.J.; Buonanno, F.S.; New, P.F.; Kistler, J.P.; McGinnis, B.D.; Pykett, I.L.; Taveras, J.M.

    1983-02-01

    Saturation recovery nuclear magnetic resonance (NMR) images and metrizamide computed tomography (CT) scans were obtained in an adult patient with a clinical history suggestive of syringomyelia. Both NMR and CT studies showed low lying cerebellar tonsils. The CT study demonstrated central cavitation of the spinal cord from the midthoracic to midcervical levels but could not exclude an intramedullary soft tissue mass at the cervico-medullary junction. The NMR images in transverse, coronal, and sagittal planes demonstrated extension of an enlarged central spinal cord cerebrospinal fluid space to the cervico-medullary junction. This was felt to be strong evidence for exclusion of an intramedullary soft tissue mass and in favor of a diagnosis of Arnold-Chiari Type I malformation with hydromyelia. The noninvasive nature of spinal cord and cervico-medullary junction evaluation with NMR is emphasized.

  18. Nature versus nurture: Functional assessment of restoration effects on wetland services using Nuclear Magnetic Resonance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Sundareshwar, P. V.; Richardson, C. J.; Gleason, Robert A.; Pellechia, Perry J.; Honomichl, Shawn

    2009-02-01

    Land-use change has altered the ability of wetlands to provide vital services such as nutrient retention. While compensatory practices attempt to restore degraded wetlands and their functions, it is difficult to evaluate the recovery of soil biogeochemical functions that are critical for restoration of ecosystem services. Using solution 31P Nuclear Magnetic Resonance Spectroscopy, we examined the chemical forms of phosphorus (P) in soils from wetlands located across a land-use gradient. We report that soil P diversity, a functional attribute, was lowest in farmland, and greatest in native wetlands. Soil P diversity increased with age of restoration, indicating restoration of biogeochemical function. The trend in soil P diversity was similar to documented trends in soil bacterial taxonomic composition but opposite that of soil bacterial diversity at our study sites. These findings provide insights into links between ecosystem structure and function and provide a tool for evaluating the success of ecosystem restoration efforts.

  19. The morphology of C–S–H: Lessons from {sup 1}H nuclear magnetic resonance relaxometry

    SciTech Connect

    Valori, A.; McDonald, P.J.; Scrivener, K.L.

    2013-07-15

    {sup 1}H nuclear magnetic resonance has been applied to cement pastes, and in particular calcium silicate hydrate (C–S–H), for the characterisation of porosity and pore water interactions for over three decades. However, there is now renewed interest in the method, given that it has been shown to be non-invasive, non-destructive and fully quantitative. It is possible to make measurements of pore size distribution, specific surface area, C–S–H density and water fraction and water dynamics over 6 orders of magnitude from nano- to milli-seconds. This information comes in easily applied experiments that are increasingly well understood, on widely available equipment. This contribution describes the basic experiments for a cement audience new to the field and reviews three decades of work. It concludes with a summary of the current state of understanding of cement pore morphology from the perspective of {sup 1}H NMR.

  20. Sub-nanoliter nuclear magnetic resonance coils fabricated with multilayer soft lithography

    NASA Astrophysics Data System (ADS)

    Lam, Matthew H. C.; Homenuke, Mark A.; Michal, Carl A.; Hansen, Carl L.

    2009-09-01

    We describe the fabrication and characterization of sub-nanoliter volume nuclear magnetic resonance (NMR) transceiver coils that are easily amenable to integration within PDMS-based microfluidics. NMR coils were constructed by the injection of liquid metal into solenoidal cavities created around a microchannel using consecutive replica molding and bonding of PDMS layers. This construction technique permits the integration of NMR coils with solenoidal, toroidal or other three-dimensional geometries within highly integrated microfluidic systems and are one step toward NMR-based chemical screening and analysis on chip. The current proof-of-principle implementation displays limited sensitivity and resolution due to the conductivity and magnetic susceptibilities of the construction materials. However, NMR measurements and finite-element simulations made with the current device geometry indicate that optimization of these materials will allow for the collection of spectra from sub-millimolar concentration samples in less than 1 nL of solution.