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101.
Sengupta K Alzamora M Fontes MB Sampathkumaran EV Ramos SM Hering EN Saitovitch EM Paulose PL Ranganathan R Doert T Jemetio JP 《J Phys Condens Matter》2012,24(9):096004
The influence of external pressure on the electrical transport and magnetic properties of EuCu(2)As(2), crystallizing in a ThCr(2)Si(2)-type structure, is reported. The system is known to be an antiferromagnet below T(N) ≈ 15 K in the absence of external magnetic fields. We find that there is a gradual reduction of T(N) with the application of a magnetic field with an extrapolated value of the critical field of around 18 kOe which can drive T(N) to zero. Electrical resistivity under pressure (<11 GPa) reveals that the magnetic ordering temperature is pushed up dramatically to higher temperatures which is quite interesting if compared with the behavior in isostructural FeAs-based systems containing Eu. Above 7 GPa, the pressure-induced state appears to be ferromagnetic. The results thus reveal interesting changes in the magnetic ordering behavior of this compound with increasing pressure and magnetic fields. 相似文献
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103.
Christian Hering 《Journal of multivariate analysis》2010,101(6):1428-1433
A probabilistic interpretation for hierarchical Archimedean copulas based on Lévy subordinators is given. Independent exponential random variables are divided by group-specific Lévy subordinators which are evaluated at a common random time. The resulting random vector has a hierarchical Archimedean survival copula. This approach suggests an efficient sampling algorithm and allows one to easily construct several new parametric families of hierarchical Archimedean copulas. 相似文献
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109.
M.M. Ivanenko H. Handreck J. Göthel W. Fuss K.-L. Kompa P. Hering 《Applied physics. B, Lasers and optics》1997,65(4-5):577-582
2 to the CHClF2/He mixture irradiated by a Q-switched CO2 laser leads to oxidation of the dissociation product according to the reaction: CF2+NO2→COF2+NO. The resulting COF2 with a 13C content near 50% is easy to convert to CO2 or CO for further enrichment by a nonlaser process. We measured the dependence of the fraction of dimerised CF2 on NO2 pressure pNO2 and the amount of NO2 required to suppress dimerisation on the dissociation yield. Both agree with a kinetic model using known rate constants.
For the range of the dissociation parameters (13CF2 yield of 10% per pulse, isotope selectivity of 130) of practical interest, 95% of the CF2 produced is oxidized at pNO2≈1/2pCHClF2. In the absence of NO2, major (20%–35%) losses of CF2 at the metal walls of the irradiation system were observed. Addition of NO2 suppresses them. For comparison, we also used O2 as a scavenger in CHClF2 dissociation. NO2 is by orders of magnitude more efficient.
Received: 21 January 1997/Revised version: 23 March 1997 相似文献
110.
2 laser using a miniature water spray is demonstrated. An ablation threshold of 1.4 J/cm2, an optimal energy density of 9–10 J/cm2, and a corresponding specific ablation energy of 25–30 J/mm3 are found for pig thighbone compacta at λ=9.57 μm and a beam waist diameter of 0.5 mm. The water spray alleviates tissue
carbonization even at high laser pulse repetition rates and increases ablation efficiency.
Received: 9 March 1998/Revised version: 6 July 1998 相似文献