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1.
Within the framework of the method of a density matrix, differential equations are obtained that describe the evolution of the modes of magnetization <Î+>, <Î+ z >, and <Î+ z 2> for a spin system containing a nucleus with a 1/2 spin connected scalarly with the quadruple nucleus of the spin S = 1 in the presence of crosscorrelation between the dipole ISinteractions, anisotropy of the chemical shift of the I and S nuclei, and quadruple interaction of the S nucleus. The equations are used for analysis of the evolution of the intensities of each line in the triplet of the Raman spectrum of the 1/2 spin. Expressions for the times of crossrelaxation and the times of transverse relaxation of each of the lines of the triplet are obtained.  相似文献   

2.
The high-spin states of 93Mo have been studied by a 82Se( 16O, 5n) 93Mo reaction at a beam energy of 100 MeV using techniques of in-beam -ray spectroscopy. Measurements of -t, --t coincidences, -ray angular distributions and -ray linear polarizations were performed. The high-spin isomer was found as a (39/2-) state at about 9.7 MeV. The near-yrast states in 93Mo were interpreted using the weak-coupling picture of a d5/2 neutron to a neutron magic core nucleus 92Mo.  相似文献   

3.
A simple quark pair creation model is introduced to study exclusive decays of {c_J} into baryon-antibaryon pairs. With this simple model, some exclusive decay processes, for example, {c0} B¯ (B = ,0,-) are investigated and their decay widths are evaluated by inclusion of the properties of outgoing baryons, and the results show that the strengthened decay channels {c_J} ¯(J = 0, 2) are easily understood by considering only the color singlet contribution of P-wave charmonium.  相似文献   

4.
Excited states in 110Sn and 111Sn nuclei have been investigated using in-beam -ray spectroscopic methods. An 16O beam with an energy of 60-80MeV was used to bombard a 98Mo target. On the basis of the relative excitation functions, -ray angular distributions, - and -time distributions, -ray multiplicity and total energy data, the level schemes of 110Sn and 111Sn have been studied and extended up to Eexc 11.5MeV, I = 24, and Eexc 11.1MeV and I = (51/2), respectively. An extension of the intruder, g.s. and negative-parity bands, as well as 5 new band-like structures are proposed in 110Sn. The nature of newly introduced collective band 8 as well as 10+ states fed in the decay of the collective band is discussed. In the 111Sn nucleus an intruder band based on the 23/2- state has been reinvestigated and the extension of the g.s. band and second negative-parity band is given. Evidence for neutron-core coupling in 111Sn is found. The structure and systematics of excited states in light Sn isotopes is discussed.  相似文献   

5.
Faceting is a well documented phenomenon known both for surfaces and interfaces, particularly, grain boundaries (GBs). Faceting can be considered as a phase transition when the original surface or GB dissociates onto flat segments whose energy is less than that of the original surface or GB. For the investigation of GB faceting a cylindrical Cu bicrystal with an island grain was grown by the Bridgman technique. Grain 1 in this bicrystal is completely surrounded by grain 2. The dissociation 9 3 + 3 proceeds during the growth of the bicrystal. The twins appear instead of {111}1/{115}2 or (110)9CSL facet. GB faceting was studied at 1293 K, 1073 K, and 873 K. The profiles of the GB thermal groove were analysed by atomic force microscopy. Wulff-Herring plots and GB phase diagrams have been constructed for the 3, 9 and 9 + 3 GBs. With increasing temperature the facets with low-density CSL-planes disappear in the GB shape. GB roughening phase transition can be responsible for this phenomenon.  相似文献   

6.
Using the DFT/B3LYP method with the base set 631G**, we carried out calculation of the frequencies of the normal vibrations of porphin and of its five isotopic types. Scaling of force constants for outofplane vibrations has been performed in independent natural coordinates. The symmetry coordinates are introduced and a force field for outof plane vibrations of a porphin molecule in independent coordinates of symmetry is obtained. A new correlation of the frequencies of vibrations in the type of the symmetry B 1u for the isotopic type of the d 2 porphin molecule is suggested on the basis of discrete analysis of the distribution of a potential energy.  相似文献   

7.
The very neutron-deficient 117Ba nuclei were produced in 58Ni-induced reactions on a 63Cu target and selected for spectroscopic studies by using BaF+ molecules formed in the ion source of the GSI on-line mass separator. The -decay of 117Ba was investigated by means of the total absorption -ray spectrometer and a telescope for -delayed particle detection. In the analysis combining the -delayed -ray and proton data the energy window available for -delayed proton emission, the branching ratios for proton transitions to the 116Xe levels and the -feeding of the -ray and proton-emitting 117Cs states were determined. The -strength function for 117Ba derived from the measured -feeding distribution revealed the existence of a broad resonance structure at 117Cs excitation energy of about 4-5 MeV. The results of the -delayed proton studies and -strength measurements are confronted with theoretical predictions.  相似文献   

8.
Resonance Raman spectra (RRS) of Co(II) and Co(III)5,10,15,20tetrakis(4Nmethylpyridinium)porphyrin ((CoII(TmpyP4), and CoIII(TMPyP4)) in aqueous solutions at different pH as well as in organic solvents (methanol, ethanol, DMSO, DMF) are obtained. The increased sensitivity of the oscillation frequencies 2, 4, 8, and 6 — the markers of the oxidation state of a metal — to the nature of an axial ligand has been revealed. For CoIII(TmpyP4), the shifts of the indicated frequencies in extracoordination have turned out to be twofold larger than those for CoII(TmpyP4). The spectral effects observed are related to different electron influence of the extraligands on the system of the porphyrin ring. In the case of Co(III)porphyrin, interaction of the d orbitals of the metal and the e g *orbitals of the macrocycle is more efficient since its ionic radius is smaller than for the Co(II)complex. For CoIII(TmpyP4), a linear correlation between the oscillation frequencies 2, 4, 8, and 6 and the experimental Gutmann parameters characterizing the electronacceptor properties of solvents is found.  相似文献   

9.
Four new Hofmanntype complexes, M(DMTF)2Ni(CN)4, (where DMTF is dimethylthioformamide, M=Mn, Cd, Co, or Ni) were synthesized and their structure was determined by an elemental analysis and infrared spectroscopy. The IR spectra of DMTF and its nickel tetracyanine complexes with Mn(II), Cd(II), Co(II), and Ni(II) have been investigated within the range 4000–400 cm–1. The frequency shifts in the metal complexes agree with the assignment of the CS and CN frequencies. The complexes consist of infinite planar polymer layers of |MNi(CN)4|. Ndimethylthioformamide is coordinated to this layer from above and below; it is a monodentate ligand and is Sbonded through the metal atom in these complexes.  相似文献   

10.
This paper describes the VFS-3M videophotometric system designed for automatic remote recording of images and parameters of optical radiations following lightning discharges from aboard the Russian segment of the International space station. The characteristics of the system and the possibilities of recording such types of radiation as Red Sprites and Blue Jets are given.  相似文献   

11.
A misunderstanding persists between Stuart and me, which I do my best to clarify. Bayesian inverse subjectivities versus relativistic covariance and physical intersubjectivity are discussed. A joint number of chances formalism taking care of the propagation of the probability of causes is proposed.  相似文献   

12.
We consider cosmology in the framework of a material reference system of particles, including the effects of quantum recoil induced by closed-string probe particles. We find a time-dependent contribution to the cosmological vacuum energy, which relaxes to zero as 1/t 2 for large times t. If this energy density is dominant, the Universe expands with a scale factor R(t)t 2. We show that this possibility is compatible with recent observational constraints from high–redshift supernovae, and may also respect other phenomenological bounds on time variation in the vacuum energy imposed by early cosmology.  相似文献   

13.
Finite squareL×L Ising lattices with ferromagnetic nearest neighbor interaction are simulated using the Swendsen-Wang cluster algorithm. Both thermal properties (internal energyU, specific heatC, magnetization |M|, susceptibility) and percolation cluster properties relating to the physical clusters, namely the Fortuin-Kasteleyn clusters (percolation probability P , percolation susceptibility p, cluster size distributionn l) are evaluated, paying particular attention to finite-size effects. It is shown that thermal properties can be expressed entirely in terms of cluster properties, P being identical to |M| in the thermodynamic limit, while finite-size corrections differ. In contrast, p differs from even in the thermodynamic limit, since a fluctuation in the size of the percolating net contributes to, but not to p. NearT c the cluster size distribution has the scaling properties as hypothesized by earlier phenomenological theories. We also present a generalization of the Swendsen-Wang algorithm allowing one to cross over continuously to the Glauber dynamics.  相似文献   

14.
In situ transmission electron microscopy observations of the dislocation motion at vicinity of the /' interfaces in a Ni-base superalloy have been performed. They allow to identify the elemental mechanisms, under stress and at different temperatures, of the deformation propagation across the interfaces. It is shown that some of the mechanisms already analyzed in the literature occur. Moreover, new processes are revealed such as the formation of small dislocation pile-ups on the /' interfaces. Such a configuration, which increases the local stress, favors the overcoming of the interface.These observations together with new considerations on stresses are taken into account for proposing a new equilibrium equation for a dislocation abutting on a /' interface. This equation involves all the stress components acting on a dislocation: the applied stress, the misfit stress, the friction stress, the stress concentration due to the dislocation pile-up and the image stress.  相似文献   

15.
-particles from fusion reactions in a DT magnetized plasma are confined inside the plasma not only by magnetic fields but also by induced electric fields which are due to the different mobilities of -particles and electrons. Criteria are derived for the -confinement in a cylindrical plasma, inertially confined by a heavy liner. It is observed that the suprathermal population in the DT plasma will influence the overall dynamics.  相似文献   

16.
A photometric and fluorimetric study of the acid-base behavior of 2,2-diquinolyl and 2,2,2-terpyridyl was performed. In sulfuric acid medium, the doubly charged 2,2-diquinolynium ion undergoes the first dissociation atH 0=0.20±0.09, as determined by fluorimetry (ex=336 nm, em=424 nm). Photometric titration is less accurate because of the overlapping of the absorption spectra. The second dissociation constant of 2,2-diquinolyl was determined by fluorimetric titration (ex=336 nm, em=420 nm), obtaining a value of 3.67±0.03. The triply charged 2,2,2-terpyridyl molecule was found to undergo the first dissociation atH 0=–7.17±0.04, as determined by fluorimetric titration (ex=316 nm, em=350 nm), in aqueous sulfuric acid medium. Photometric titration (=335 nm) was performed in the presence of 6.5% ethanol because of the low solubility of the compound in water. In this ethanolicwater medium, a value of the dissociation constant atH 0=–7.39±0.03 was calculated. The second dissociation constant was determined to be 2.81±0.12 by photometric titration at 285 nm, and values of 4.03±0.26 and 4.16±0.20 were found for the third dissociation constant by photometric titrations at 320 and 295 nm, in 10% ethanol, in close agreement with previously reported values. The fluorimetric titration profile obtained by exciting at 274 nm and measuring the fluorescence emission at 350 nm, in the zone betweenH 0=–3 and pH=10, is complicated by the several equilibria involved.  相似文献   

17.
In order to indentity the corrosion products formed on steel surfaces from 57Fe Mössbauer spectroscopy, detailed Mössbauer parameters have been determined for various kinds of iron-oxyhydroxides: -FeOOH, -FeOOH, -FeOOH and -FeOOH. 57Fe Mössbauer measurements of the iron oxyhydroxides indicate the following results. Fe occupies a single site in -FeOOH, but below the Néel temperature as at e.g., 300 K the Mössbauer spectrum is always broad, showing a distribution of the strength of the magnetic exchange interactions. Its shape depends on the grain-size and synthetic methods of the specimen. Fe occupies 3 sites in -FeOOH. High-purity reagents of -FeOOH always contain small amounts of -FeOOH and their Néel temperatures depend on the synthetic methods of the specimen. Mössbauer spectroscopy of the synthetic -FeOOH shows very broad distribution of the hyperfine magnetic fields.  相似文献   

18.
IR integrated photonic amplifiers at 1.55m operation will have good foreground in optical phasedarray radars for splitters and signal processing. The saturation gain characteristics of IR integrated photonic waveguide amplifiers (taken Er3+Yb3+ co-doped phosphate glass waveguide amplifiers as an example) are studied theoretically. For the homemade laser glass materials the calculated saturation intensities are 2.22kw /cm2 for signal and 10.15kw/cm2 for pump. The effects of absorption saturation of signal and pump lights on the gain of amplifiers are discussed.  相似文献   

19.
The characteristic factors of the gallium and vanadium chelates with the ligands 4(2pyridylazo)resorcinol (PAR) and xylenol orange (XO) have been determined with the aid of the principle of correction, which makes it possible to eliminate the influence of the surplus ligand in the solution of its chelate with methane (which makes calculation easier) and thereby provides a more acceptable method in comparison with others. The real molar coefficients of extinction of the chelates Ga and V with PAR and XO have been determined and a detailed calculation of the stoichiometric ratios of chelates has been made. The results have shown that the chelates formed have the following structure: Ga(PAR), Ga(XO), V(PAR)2, and V(XO).  相似文献   

20.
It is well known that in the non-depleted pump approximation, the efficiency of a second harmonic generation (SHG) of a guided mode in a non-linear optical waveguide increases quadratically with the interaction length (P 2 L 2), and linearly (P 2 L) in the erenkov regime. The efficiency of the erenkov SHG in the waveguide with a non-linear substrate and linear guiding layer is known to be strongly peaked at a particular pump wavelength and a particular waveguide thickness, with the erenkov angle approaching zero. The known theory predicts an infinite efficiency value at the peak, however. In this contribution, a simple integral expression for the SHG efficiency in the erenkov regime is derived. For large erenkov angles and interaction lengths it yields the expected P 2 L dependence, while in the limit of small erenkov angles the dependence is found to have the form of P L 3/2, possessing also a finite value at the efficiency peak. The condition determining the accurate position of the efficiency peak in the waveguide thickness–pump wavelength plane is given, too.  相似文献   

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