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1.
We investigate the phase diagram of the anisotropic spin-1/2 triangular lattice antiferromagnet, with interchain diagonal exchange J' much weaker than the intrachain exchange J. We find that fluctuations lead to a competition between (commensurate) collinear antiferromagnetic and (zigzag) dimer orders. Both states differ in symmetry from the spiral order known to occur for larger J', and are therefore separated by quantum phase transitions from it. The zero-field collinear antiferromagnet is succeeded in a magnetic field by magnetically ordered spin-density-wave and cone phases, before reaching the fully polarized state. Implications for the anisotropic triangular magnet Cs2CuCl4 are discussed.  相似文献   
2.
On the basis of the electron Boltzmann equation and of the balances for the charge carriers (e, H+, H2+, H3+), the H-atoms and the metastable H(2s)-atoms for the H/H2-mixture the behaviour of the weakly turbulent, band-like electron-beam discharge plasma in hydrogen has been calculated taking into account the main collision and transport processes. In dependence of the normalized discharge length, the life time of the neutral particles in the band-like plasma and the electron beam generated turbulence energy density the ionization and dissociation budget and in particular the most important electron-heavy particle collision rates, which appear in the balance equation system, are investigated in the present part of our paper. In a second part the results related to the budget of the ions and the metastable atomic state will be reported and an analysis of the main processes in the balances will be made.  相似文献   
3.
We investigate interactions between spins of strongly correlated electrons subject to the spin-orbit interaction. Our main finding is that of a novel, spin-orbit mediated anisotropic spin-spin coupling of the van der Waals type. Unlike the standard exchange, this interaction does not require the wave functions to overlap. We argue that this ferromagnetic interaction is important in the Wigner crystal state where the exchange processes are severely suppressed. We also comment on the anisotropy of the exchange between spins mediated by the spin-orbital coupling.  相似文献   
4.
Abstract— The Fourier-transform infrared spectra of chloroform-d solutions of conjugated imines CH3CH=CHCH=NCH(CH3)2 and CH3CH2CH=CHCH=CHCH=NCH(CH3)2 and the related protonated species with HCl, HBr, HI, trichloro, dichloro, monobromo and monochloroacetic acids or propionic acid are presented. The effects of conjugation and protonation are examined. The results show that conjugation slightly increases the basicity of the Schiff bases. HCl, HBr and HI protonate the Schiff bases completely. The carboxylic acids protonate partially depending on their p K a, values. When the Schiff base contains two (or more) C=C bonds conjugated with C=N, the main C=C stretching band undergoes a strong intensification showing that sizeable dipole moment variations occur along the conjugated chain.  相似文献   
5.

An efficient synthesis of 5,5-diallyl-substituted oxazolidinone derivatives, based on reductive diallylation of available α-amino acids, was developed. It was demonstrated that the obtained oxazolidinones can be readily converted into the corresponding derivatives of 3-azaspiro[4,4]-non-7-en-2-one via the metathesis reaction in the presence of the 1st generation Grubbs catalyst.

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6.
The investigation of the impact of the vibrationally excited molecules in the electronic ground state was performed by simultaneously solving a balance equation system for the main charge carriers, the H atoms, the metastable H atoms, the H2 molecules in the different vibrational states and for the power transfer of the electrons in the beam discharge mixture plasma. The balance equations for the vibrational states include in particular one-quantum step excitation and deexcitation, electronic excitation, dissociation and ionization from each vibrational level in electron collisions as well as the finite life time of these states because of the gas transfer through the band-like plasma. A main finding is that due to the additional impact of vibrationally excited molecules there is a marked enhancement of the resulting dissociation and ionization degree in the beam discharge plasma at medium power input from the turbulent electric field. For discharge parameters of practical interest the ionization and dissociation budget, the population of the vibrational states, the different energy dissipation processes and the energy pumping into the ladder of the vibrational states were calculated and discussed in detail.  相似文献   
7.
Using the random phase approximation, we show that a crossed-chains model of spin-1/2 Heisenberg chains with frustrated interchain couplings has a nondimerized spin-liquid ground state in 2D, with deconfined spinons as the elementary excitations. The results are confirmed by a bosonization study, which shows that the system is an example of a "sliding Luttinger liquid." In an external field, the system develops an incommensurate field-induced long-range order with a finite transition temperature.  相似文献   
8.
In the first part [1] of our paper a kinetic model for the band-like beam discharge plasma in hydrogen was derived, numerically obtained results on the ionization and dissociation degree were presented and a detailed explanation of the influence of the electron kinetic properties on the macroscopic plasma behaviour was given. Continuing these investigations, we now report and discuss the results on the ion- and metastable atom-budget. On this basis an analysis is made of the resulting balance equation system with a view to finding the most important physical processes, and a simplified equation system is derived which allows to interpret the essential features of the macroscopic plasma properties.  相似文献   
9.
We present analysis of the interacting quantum wire problem in the presence of magnetic field and spin-orbit interaction. We show that an interesting interplay of Zeeman and spin-orbit terms, facilitated by the electron-electron interaction, results in the spin-density wave state when the magnetic field and spin-orbit axes are orthogonal. This strongly affects charge transport through the wire: With the spin-density wave stabilized, single-particle backscattering off a nonmagnetic impurity becomes irrelevant. The sensitivity of the effect to the direction of the magnetic field can be used for experimental verification of this proposal.  相似文献   
10.
The use of spray drying to obtain powders of complex oxides with a garnet structure has demonstrated. The processes occurring during heating of the synthesized oxide–salt product, leading to the formation of a material with a garnet structure, have been investigated using DTA, TGA, XPS, and XRD. It has been shown that a single-phase garnet structure of system (Y x Gd(3–x))3Al5O12 can be synthesized over the entire range of compositions.  相似文献   
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