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An NMR pulse sequence is proposed for the simultaneous determination of side chain chi1 torsion-angle related (3)J(N,Cgamma) and (3)J(C', Cgamma) couplings in aromatic amino acid spin systems. The method is of the quantitative J correlation type and takes advantage of attenuated (15)N and (1)H transverse relaxation by means of the TROSY principle. Unlike previously developed schemes for the measurement of either of the two coupling types, spectra contain internal reference peaks that are usually recorded in separate experiments. Therefore, the desired information is extracted from a single rather than four data sets. The new method is demonstrated with uniformly (13)C/(15)N labeled Desulfovibrio vulgaris flavodoxin, which contains 14 aromatic out of 147 total amino acid residues.  相似文献   

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The cross sections of Ni(n,x)~(58(m g))Co,Ni(n,x)~(60m)Co,Ni(n,x)~(61)Co and Ni(n,x)~(62m)Co reactions induced by neutrons around 14 MeV were measured in this work and calculated by a previously developed formula in this work.The neutron flux was determined using the monitor reaction ~(27)Al(n,α)~(24)Na and the neutron energies were measured with the method of cross-section ratios for ~(90)Zr(n,2n)~(89)Zr to ~(93)Nb(n,2n)~(92m)Nb reactions.  相似文献   

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The reaction 48Ca(3He, t)48Sc to the low-lying even spin states has been studied as a pure sequential (3He, α) (α,t) process using an exact finite-range formalism. It is found that the strength of the cross-sections to these states is under-predicted by large factors. The consideration of second-order processes via the inelastic channels also fails to account for the strength of these states. The (3He, t) discrepancy still exists.  相似文献   

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Based on WeinbergoSalam theory the bremsstrahlung neutrino energy loss for nuclei ~(24)Mg, ~(28)Si, ~(32)S, ~(40)Ca and ~(56)Fe are investigated in strong electron screening. Our results are compared with those of Dicus' and show that the latter are higher by 2 orders of magnitude in the density-temperature region of 10~8 g/cm~3 ≤ρ/μ_e≤10~(11) g/cm~3 and 2.5 ≤ T_9 ≤4.5. On the other hand, the factor C shows that the maximum differences are 99.16%, 99.13%, 99.12%, 99.055%, 99.040% corresponding to the nuclei ~(24)Mg, ~(28)Si, ~(32)S, ~(40)Ca and ~(56)Fe.  相似文献   

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Based on Weinberg-Salam theory the bremsstrahlung neutrino energy loss for nuclei 24Mg,28Si,32S,40Ca and 56Fe are investigated in strong electron screening.Our results are compared with those of Dicus' and show that the latter are higher by 2 orders of magnitude in the density-temperature region of 108 g/cm3 ρ/μe 1011 g/cm3 and 2.5 T9 4.5.On the other hand,the factor C shows that the maximum differences are 99.16%,99.13%,99.12%,99.055%,99.040% corresponding to the nuclei 24Mg,28Si,32S,40Ca and 56Fe.  相似文献   

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The structure of K0.92(2) Zn0.08(2) H1.92(2) (PO4) was determined using single-crystal X-ray diffraction. The crystal structure of the Zn-KDP belonged to the tetragonal space group $ \mathrm{I}\overline{4}2\mathrm{d} $ , with cell parameters of a?=?b?=?7.4487(5)?Å and c?=?6.9703(5)?Å, 386.73(5) Å3, Z?=?4, and R?=?0.023. Zn2+ ions were used as substitutes for K+ ions with hydrogen vacancy. The Zn-KDP single crystals were submitted to further Raman, infrared, and 1H NMR studies to investigate chemical group functionalisation, possible bonding between the organic and inorganic materials, and partial substitution of K+ by Zn2+. The latter partial substitution was confirmed by the deviation of IR frequencies for O–H stretching, the variation of IR and Raman frequencies for stretching and bending vibrations ν(PO4) of H2PO4, and the appearance of additional Raman (147, 386 and 481 cm?1) vibrational bands. Electrical conductivity measurements were performed on polycrystalline pellets of Zn-KDP and pure KDP at room temperatures (RT) of up to 473K. In both cases, a conductivity jump close to 453K was observed, and a stronger increase of conductivity was measured.  相似文献   

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We determine the radiative decay amplitudes for the decay into D* and $ \bar{{D}}$ $ \gamma$ , or D * s and $ \bar{{D}}_{s}^{}$ $ \gamma$ of some of the charmonium-like states classified as X , Y , Z resonances, plus some other hidden charm states which are dynamically generated from the interaction of vector mesons with charm. The mass distributions as a function of the $ \bar{{D}}$ $ \gamma$ or $ \bar{{D}}_{s}^{}$ $ \gamma$ invariant mass show a peculiar behavior as a consequence of the D * $ \bar{{D}}^{*}_{}$ nature of these states. The experimental search of these magnitudes can shed light on the nature of these states.  相似文献   

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The model of a three-particle proton cluster coupled to the quadrupole vibrational field is applied to129I. The energy spectrum and spectroscopic factors, as obtained in a (3He,d) stripping reaction, are calculated and compared with experimental data. With the wave functions obtained magnetic-dipole and electric-quadrupole moments are derived.  相似文献   

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利用SU(2)q,s量子代数的两参数变形振子实现构造出与Perelomov相干态形式不同的SU(2)q,s相干态.证明了SU(2)q,s,量子代数的表示基是正交的,并讨论了它的相干态的归一性和完备性.指出SU(2)q,s相干态的相干性受参数q,s的影响,它比单参数变形SU(2)q相干态更具一般性.  相似文献   

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Ferromagnetic resonance in epitaxial (Bi,Lu)3(Fe,Ga)5O12 films grown on Gd3Ga5O12(210) substrates is investigated. The spectrum contains a number of peaks, the most intense of which is related to the bulk of the film and the transition layer at the film-substrate interface. Most of the film volume is characterized by reduced magnetic anisotropy. The azimuthal and polar dependences of the resonance field exhibit 180° symmetry.  相似文献   

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Li_(6.4)La_3 Zr_(1.4)Ta_(0.6)O_(12)(LLZTO) is a promising inorganic solid electrolyte due to its high Li+conductivity and electrochemical stability for all-solid-state batteries.Mechanical characterization of LLZTO is limited by the synthesis of the condensed phase.Here we systematically measure the elastic modules,hardness,and fracture toughness of LLZTO poly crystalline pellets of different densities using the customized environmental nanoindentation.The LLZTO samples are sintered using the hot-pressing method with different amounts of Li_2CO_3 additives,resulting in the relative density of the pellets varying from 83% to 98% and the largest grain size of 13.21 ± 5.22 μm.The mechanical properties show a monotonic increase as the sintered sample densifies,elastic modulus and hardness reach 158.47± 10.10 GPa and 11.27± 1.38 GPa,respectively,for LLZTO of 98% density.Similarly,fracture toughness increases from 0.44 to 1.51 MPa·m~(1/2),showing a transition from the intergranular to transgranular fracture behavior as the pellet density increases.The ionic conductivity reaches 4.54 × 10~(-4) S/cm in the condensed LLZTO which enables a stable Li plating/stripping in a symmetric solid-state cell for over 100 cycles.This study puts forward a quantitative study of the mechanical behavior of LLZTO of different microstructures that is relevant to the mechanical stability and electrochemical performance of all-solid-state batteries.  相似文献   

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The mineral lewisite, (Ca, Fe, Na)2(Sb, Ti)2O6(O, OH)7, an antimony-bearing mineral, has been studied by Raman spectroscopy. A comparison is made with the Raman spectra of other minerals, including bindheimite, stibiconite, and roméite. The mineral lewisite is characterised by an intense sharp band at 517 cm?1 with a shoulder at 507 cm?1 assigned to SbO stretching modes. Raman bands of medium intensity for lewisite are observed at 300, 356, and 400 cm?1. These bands are attributed to OSbO bending vibrations. Raman bands in the OH stretching region are observed at 3200, 3328, 3471 cm?1, with a distinct shoulder at 3542 cm?1. The latter is assigned to the stretching vibration of OH units. The first three bands are attributed to water stretching vibrations. The observation of bands in the 3200–3500 cm?1 region suggests that water is involved in the lewisite structure. If this is the case then the formula may be better written as (Ca, Fe2+, Na)2(Sb, Ti)2(O, OH)7 xH2O.  相似文献   

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The ground state rotational bands of the N = Z nuclei (72)Kr, (76)Sr, and (80)Zr have been extended into the angular momentum region where rotation alignment of particles is normally expected. By measuring the moments of inertia of these bands we have observed a consistent increase in the rotational frequency required to start pair breaking, when compared to neighboring nuclei. (72)Kr shows the most marked effect. It has been widely suggested that these "delayed alignments" arise from np-pairing correlations. However, alignment frequencies are very sensitive to shape degrees of freedom and normal pairing, so the new experimental observations are still open to interpretation.  相似文献   

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Based on the rank analysis method, algorithmization idea, and symbolic computation, in this paper we have presented a method to construct the conservation laws for nonlinear evolution equations. The polynomial conservation laws for K (n 2, n) equations and mnK(m, n) equations are found by using of this approach and some new results have been obtained.  相似文献   

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We show that the composition of not only two SO(3,1) boosts, but also that of two SO(n,1) boosts for anyn 2, is basically an SO(2,1) problem and hence can be analysed completely using SL(2,R) matrices. By computing the expression for the Thomas/Wigner angle directly using SL(2,R) matrices we show that this approach results in considerable economy of algebra.  相似文献   

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The 46Ti(p, γ)47V, 50Cr(p, γ)51Mn, 58Ni(α,γ)62Zn and58Ni (α, p)61Cu cross sections have been measured in the energy range of interest for stellar nucleosynthesis during oxygen and silicon burning. The results are compared with statistical theory calculations which attempt to treat excited state effects and the γ-ray channel more realistically than previous calculations.  相似文献   

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