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1.
Parameter analysis for a nuclear magnetic resonance gyroscope based on ~(133)Cs–~(129)Xe/~(131)Xe
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《中国物理 B》2017,(2)
We theoretically investigate several parameters for the nuclear magnetic resonance gyroscope based on ~(133)C_(s–)~(129)Xe/~(131)Xe. For a cell containing a mixture of ~(133)Cs at saturated pressure, we investigate the optimal quenching gas(N_2) pressure and the corresponding pump laser intensity to achieve 30% ~(133)Cs polarization at the center of the cell when the static magnetic field B0 is 5 μT with different ~(129)Xe/~(131)Xe pressure. The effective field produced by spin-exchange polarized ~(129)Xe or ~(131)Xe sensed by ~(133)Cs can also be discussed in different~(129)Xe/~(131)Xe pressure conditions. Furthermore,the relationship between the detected signal and the probe laser frequency is researched. We obtain the optimum probe laser detuning from the D2(6~2S_(1/2)→ 6~2P_(3/2)) resonance with different ~(129)Xe/~(131)Xe pressure owing to the pressure broadening. 相似文献
2.
XIE Bosun 《声学学报:英文版》2009,28(2):116-128
A method to correct the measured head-related transfer functions (HRTFs) at low frequency was proposed. By analyzing the HRTFs from the spherical head model at low frequency, it is proved that below the frequency of 400 Hz, magnitude of HRTF is nearly constant and the phase is a linear function of frequency both for the far and near field. Therefore, if the HRTFs above 400 Hz are accurately measured by experiment, it is able to correct the HRTFs at low frequency by the theoretical model. The results of calculation and subjective experiment show that the feasibility of the proposed method. 相似文献
3.
Natural xenon, contained in a ceil at a pressure of 6.5 atm, is frozen from 303 to 137 K on an WP-80SY NMR spectrometer. NMR signals of 129Xe atoms in gaseous, liquid and solid phases are measured at various temperatures, We found that the chemical shift of NMR signal of liquid 129Xe (expressed as ΔH) is directly proportional to the density of the sample with a coefficient of (4.73±0.05)×10-7; and the chemical shift of NMR signal of solid 129Xe (expressed as ΔH) is nearly proportional to the density of the sample with a coefficient of (5.00±0.08)×10-7. 相似文献
4.
We report a direct measurement of the imaginary part of the surface tension of water through a dynamic scheme using a thin vertical glass fiber of diameter of 3 tun with one end glued onto a cantilever beam and the other end touching a water-air interface. The frequency dependence of the dissipation factor experienced by the glass fiber is exactly calculated through measuring the phase delay with various frequencies when the glass fiber is forced to oscillate vertically. We find the same intercept at the dissipation factor axis for different frequency dependences of the dissipation factor for different depths by which the glass fiber is dipped into water. This nonzero dissipation factor at zero frequency presents direct evidence of the existence of the imaginary part of surface tension of water and yields a complex surface tension of water σ^* = 0.073 + i(0.017 ± 0.002) N/m at room temperature. 相似文献
5.
Tunable and switchable Ba 0.5 Sr 0.5 TiO 3 film bulk acoustic resonators(FBARs) based on SiO 2 /Mo Bragg reflectors are explored,which can withstand high temperature for the deposition of Ba x Sr 1 x TiO 3(BST) films at 800 C.The dc bias-dependent resonance may be attributed to the piezoelectricity of the BST film induced by an electrostrictive effect.The series resonant frequency is strongly dc bias-dependent and shifts downwards with dc bias increasing,while the parallel resonant frequency is only weakly dc bias-dependent and slightly shifts upwards at low dc bias( 45 V) while downwards at higher dc bias.The calculated relative tunability of shifts at series resonance frequency is around 2.3% and the electromechanical coupling coefficient is up to approximately 8.09% at 60-V dc bias,which can be comparable to AlN FBARs.This suggests that a high-quality tunable BST FBAR device can be achieved through the use of molybdenum(Mo) as the high acoustic impedance layer in a Bragg reflector,which not only provides excellent acoustic isolation from the substrate,but also improves the crystallinity of BST films withstanding higher deposition temperature. 相似文献
6.
Magnetoelectric Coupling in Bilayers of Pb(Zr, Ti)O3 Epoxy and Hot Pressed Manganite Perovskite
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The synthesis and magnetoclectric (ME) characterization of bilayers of Pb(Zr, Ti)O3 (PZT) and hot pressed manganite perovskite La0.7Sr0.3MnO3 (LSMO) are discussed. Very strong ME interactions are measured for the bilayers. The bilayers exhibit superior ME coupling compared to thick-film composites prepared by tape casting process. Data of the ME voltage coefficient have been obtained as functions of bias magnetic field H, temperature and frequency. The transverse coupling is stronger than the longitudinal interactions and a maximum in the ME voltage coefficient is measured at 225K. The frequency dependence of the ME voltage coefficient reveals a peak at the electromechanical resonance due to radial modes. 相似文献
7.
臧永东 武军霞 赵铁成 张生虎 毛瑞士 徐瑚珊 孙志宇 马新文 涂小林 肖国青 F. Nolden P. Hülsmann Yu. A. Litvinov C. Peschke P. Petri M. S. Sanjari M. Steck 《中国物理 C》2011,35(12):1124-1129
A resonant Schottky pickup with high sensitivity, built by GSI, will be used for nuclear mass and lifetime measurement at CSRe. The basic concepts of Schottky noise signals, a brief introduction of the geometry of the detector, the transient response of the detector, and MAFIA simulated and perturbation measured results of characteristics are presented in this paper. The resonant frequency of the pickup is about 243 MHz and can be slightly changed at a range of 3 MHz. The unloaded quality factor is about 1072 and the shunt impedance is 76 kΩ. The measured results of the characteristics are in agreement with the MAFIA simulations. 相似文献
8.
A new scheme of quantum key distribution (QKD) using frequency and time coding is proposed, in which the security is based on the frequency-time uncertainty relation. In this scheme, the binary information sequence is encoded randomly on either the centrM frequency or the time delay of the optical pulse at the sender. The central frequency of the single photon pulse is set as w1 for bit 0 and set as w2 for bit 1 when frequency coding is selected. However, the single photon pulse is not delayed for bit 0 and is delayed in τ for 1 when time coding is selected. At the receiver, either the frequency or the time delay of the pulse is measured randomly, and the final key is obtained after basis comparison, data reconciliation and privacy amplification. With the proposed method, the effect of the noise in the fiber channel and environment on the QKD system can be reduced effectively. 相似文献
9.
Natural xenon, contained in a ceil at a pressure of 6.5 atm, is frozen from 303 to 137 K on an WP-80SY NMR spectrometer. NMR signals of 129Xe atoms in gaseous, liquid and solid phases are measured at various temperatures, We found that the chemical shift of NMR signal of liquid 129Xe (expressed as ΔH) is directly proportional to the density of the sample with a coefficient of (4.73±0.05)×10-7; and the chemical shift of NMR signal of solid 129Xe (expressed as ΔH) is nearly proportional to the density of the sample with a coefficient of (5.00±0.08)×10-7. 相似文献
10.
We report theoretical calculations of the transition probability errors introduced by microwave leakage in Cs fountain clocks, which will shift the clock frequency. The results show that the transition probability errors are affected by the Ramsey pulse amplitude, the relative phase between the Ramsey field and the leakage field, and the asymmetry of the leakage fields for the upward and downward passages. This effect is quite different for the leakage fields presenting below the Ramsey cavity and above the Ramsey cavity. The leakage-field-induced frequency shifts of the NIM5 fountain clock in different cases are measured. The results are consistent with the theoretical calculations, and give an accurate evaluation of the leakage-field-induced frequency shifts, as distinguished from other microwave-power-related effects for the first time. 相似文献
11.
We have determined the temperature dependence of σ1 of 129Xe in oxygen gas. These results were obtained by measurement of the resonance frequency of 129Xe in gas samples of known densities in Xe and O2. The shift of the resonance frequency due to Xe-Xe interactions has been measured in pure Xe gas samples with improved precision. This allows the determination of σ1(Xe-O2) by subtracting out the known effect of Xe-Xe interactions in mixed Xe-O2 samples. σ1(Xe-O2) values are reported here for the temperature range 220 to 440 K. The values of σ1(Xe-O2) are adequately described by the polynomial function in p.p.m. amagat-1 σ1(Xe-O2) = - 1·061 + 3·64 × 10-3τ - 2·19 × 10-5τ2 + 9·58 × 10-8τ3 - 2·08 × 10-10τ4, where τ = (T - 300 K). It is found that the temperature dependence of σ1(Xe-O2) can be interpreted in terms of a contact interaction between Xe and the paramagnetic O2 molecule. 相似文献
12.
We have developed the nuclear spin maser oscillating at a low frequency of 34 Hz with highly polarized nuclear spins of the
noble gas element 129Xe. The system is advantageous for detecting a small frequency shift of the nuclear spin precession. We are thus planning
to apply this system to the search for an atomic electric dipole moment of 129Xe. We here report the development of the system and its performance. 相似文献
13.
T. Inoue T. Furukawa A. Yoshimi Y. Ichikawa M. Chikamori Y. Ohtomo M. Tsuchiya N. Yoshida H. Shirai M. Uchida K. Suzuki T. Nanao H. Miyatake H. Ueno Y. Matsuo T. Fukuyama K. Asahi 《Hyperfine Interactions》2013,220(1-3):59-63
The present status of an active spin maser which is being developed for an experimental search for 129Xe atomic electric dipole moment (EDM) is presented. In order to realize the long term stability of maser frequency, systematic effects for the spin maser operation were investigated. The correlations in the maser frequency with the solenoid current, the environmental field and the cell temperature were found. With the solenoid current and environmental field being stabilized and the cell temperature lowered, a frequency precision of 7.9 nHz has been achieved for the maser operation. 相似文献
14.
Romanenko KV Fonseca A Dumonteil S Nagy JB d'Espinose de Lacaillerie JB Lapina OB Fraissard J 《Solid state nuclear magnetic resonance》2005,28(2-4):135-141
129Xe NMR spectroscopy has been used to study the adsorption of Xe on multi-wall carbon nanotubes (MWCNT). The results obtained have shown the 129Xe NMR ability to probe the intercrystalline (aggregate) and the inner porosity of CNT. In particular, the effects on porosity of tubes openings by hydrogen exposure and of ball milling were examined. Dramatic changes observed in the 129Xe NMR spectra after moderate ball milling of MWCNTs were attributed to the destruction of the initial intercrystalline pore structure and to the Xe access inside the nanotubes. To examine the exchange dynamics the mixture of as-made and milled MWCNTs was studied with one- and two-dimensional (1D and 2D) 129Xe NMR. The exchange between the interior of milled nanotubes and the aggregate pores of as-made MWCNTs was fast on the NMR acquisition time scale. The Xenon exchange between the interior of the as-made MWCNTs and the large aggregate pores occurred on a longer time scale of 10 ms, as was established by 2D 129Xe NMR exchange spectroscopy. Variable temperature 129Xe NMR data were also discussed and analyzed in terms of the fast exchange approximation. 相似文献
15.
Parameter analysis for a nuclear magnetic resonance gyroscope based on bf133Cs-129Xe/131Xe
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We theoretically investigate several parameters for the nuclear magnetic resonance gyroscope based on 133Cs-129Xe/131Xe. For a cell containing a mixture of 133Cs at saturated pressure, we investigate the optimal quenching gas (N2) pressure and the corresponding pump laser intensity to achieve 30% 133Cs polarization at the center of the cell when the static magnetic field B0 is 5 μT with different 129Xe/131Xe pressure. The effective field produced by spin-exchange polarized 129Xe or 131Xe sensed by 133Cs can also be discussed in different 129Xe/131Xe pressure conditions. Furthermore, the relationship between the detected signal and the probe laser frequency is researched. We obtain the optimum probe laser detuning from the D2 (62S1/2→62P3/2) resonance with different 129Xe/131Xe pressure owing to the pressure broadening. 相似文献
16.
Z. Zhao J. Yan A. Gelberg R. Reinhardt W. Lieberz A. Dewald R. Wirowski K. O. Zell P. von Brentano 《Zeitschrift für Physik A Hadrons and Nuclei》1988,331(1):113-114
Excited states of129Xe have been investigated through the126Te(α,n)129Xe reaction at the incident energy E=16MeV by means of in-beam gamma ray spectroscopy. Numerous levels below the excitation energy of 2.5MeV were found. Spin assignments were made from side feeding excitation functions. A new level at 274.2keV, which is suggested as spin 9/2 negtive parity bandhead, was observed for the first time. 相似文献
17.
Wong-Foy A Saxena S Moulé AJ Bitter HM Seeley JA McDermott R Clarke J Pines A 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2002,157(2):235-241
Laser-polarized (129)Xe and a high-T(c)superconducting quantum interference device (SQUID) are used to obtain magnetic resonance images in porous materials at a magnetic field of 2.3 mT, corresponding to a Larmor frequency of 27 kHz. Image resolution of 1 mm is obtained with gradients of only 1 mT/m. The resolution of xenon chemical shifts in different physicochemical environments at ultralow fields is also demonstrated. Details of the circulating flow optical pumping apparatus and the SQUID spectrometer are presented. 相似文献
18.
孙献平 《原子与分子物理学报》2001,18(1):116-122
激光极化的129Xe核具有极高的非平衡极化度和长的弛豫时间,这一特点使得它能够极化转移增强液体、固体或者固体表面分子中原子核自旋极化。因而,提高了它们的核磁共振探测灵敏度和扩展了在材料和表面科学研究中的应用。综述激光极化129Xe核与其它分子中原子核之间的极化转移研究与进展,介绍相关物理机制和参数的测量。 相似文献
19.
Lowery TJ Rubin SM Ruiz EJ Spence MM Winssinger N Schultz PG Pines A Wemmer DE 《Magnetic resonance imaging》2003,21(10):1235-1239
The chemical shift sensitivity and significant signal enhancement afforded by laser-polarized 129Xe have motivated the application of 129Xe NMR to biological imaging and spectroscopy. Recent research done by our group has used laser-polarized 129Xe in biomolecular assays that detect ligand-binding events and distinguish protein conformations. The successful application of unfunctionalized and functionalized 129Xe NMR to in vitro biomolecular assays suggests the potential future use of a functionalized xenon biosensor for in vivo imaging. 相似文献
20.
Möller HE Cleveland ZI Driehuys B 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2011,212(1):109-115
In magnetic resonance imaging with hyperpolarized (HP) noble gases, data is often acquired during prolonged gas delivery from a storage reservoir. However, little is known about the extent to which relaxation within the reservoir will limit the useful acquisition time. For quantitative characterization, 129Xe relaxation was studied in a bag made of polyvinyl fluoride (Tedlar). Particular emphasis was on wall relaxation, as this mechanism is expected to dominate. The HP 129Xe magnetization dynamics in the deflating bag were accurately described by a model assuming dissolution of Xe in the polymer matrix and dipolar relaxation with neighboring nuclear spins. In particular, the wall relaxation rate changed linearly with the surface-to-volume ratio and exhibited a relaxivity of κ=0.392±0.008 cm/h, which is in reasonable agreement with κ=0.331±0.051 cm/h measured in a static Tedlar bag. Estimates for the bulk gas-phase 129Xe relaxation yielded T1bulk=2.55±0.22 h, which is dominated by intrinsic Xe-Xe relaxation, with small additional contributions from magnetic field inhomogeneities and oxygen-induced relaxation. Calculations based on these findings indicate that relaxation may limit HP 129Xe experiments when slow gas delivery rates are employed as, for example, in mouse imaging or vascular infusion experiments. 相似文献