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41.
We apply the Schwinger boson scheme to the fully screened Kondo model and generalize the method to include antiferromagnetic interactions between ions. Our approach captures the Kondo crossover from local moment behavior to a Fermi liquid with a nontrivial Wilson ratio. When applied to the two-impurity model, the mean-field theory describes the "Varma-Jones" quantum phase transition between a valence bond state and a heavy Fermi liquid. 相似文献
42.
Alavi-Harati A Alexopoulos T Arenton M Arisaka K Barbosa RF Barker AR Barrio M Bellantoni L Bellavance A Blucher E Bock GJ Bown C Bright S Cheu E Coleman R Corcoran MD Cox B Erwin AR Escobar CO Ford R Glazov A Golossanov A Gouffon P Graham J Hamm J Hanagaki K Hsiung YB Huang H Jejer V Jensen DA Kessler R Kobrak HG Kotera K LaDue J Lai N Ledovskoy A McBride PL Monnier E Nelson KS Nguyen H Prasad V Qi XR Quinn B Ramberg EJ Ray RE Santos E Senyo K Shanahan P Shields J Slater W Solomey N Swallow EC 《Physical review letters》2003,90(14):141801
The KTeV experiment at Fermilab has isolated a total of 132 events from the rare decay K(L)-->e+ e- mu+ mu-, with an estimated background of 0.8 events. The branching ratio of this mode is determined to be [2.69+/-0.24(stat)+/-0.12(syst)]x10(-9), with a radiative cutoff of M(2)(ee mu mu)/M(2)(K)>0.95. The first measurement using this mode of the parameter alpha from the D'Ambrosio-Isidori-Portolès (DIP) model of the K(L)gamma*gamma* vertex yields a result of -1.59+/-0.37, consistent with values obtained from other decay modes. Because of the limited statistics, no sensitivity is found to the DIP parameter beta. We use this decay mode to set limits on CP and lepton violation. 相似文献
43.
Calix[4]arene forms elongated nanoporous microcrystals. The pores are linear nano-channels (1.7 nm diameter) arranged in a honeycomb network. The crystals luminesce at room temperature according to a variety of processes that include monomer fluorescence (lifetime of ca. 1.1 ns), dimer fluorescence (lifetime of ca. 5.4 ns), and monomer phosphorescence (lifetime of ca. 2 s). The dimers result from pi-orbital overlap of adjacent phenol groups from neighboring nano-channels, with C-C distances of ca. 4 A. 相似文献
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Fourier transform infrared temperature studies of two semi-crystalline polyamides, nylon 12 and a terpolymer of nylon 6/66/610 are presented. The results obtained are consistent with those recently published from similar studies of an amorphous polyamide and nylon 11 and further bolster our general interpretation of the infrared spectra of polyamides. 相似文献
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R. P. Bryan J. J. Coleman R. S. Averback J. L. Klatt L. M. Miller T. M. Cockerill 《Optical and Quantum Electronics》1991,23(7):S967-S974
In recent years considerable interest has been shown in impurity-induced compositional disordering of III–V compound semiconductor devices, especially in efforts directed towards fabricating index-guided buried heterostructure lasers and other unique photonic and electronic devices. In this work we describe the study of compositional disordering induced by MeV implantation of oxygen and krypton into AlAs-GaAs superlattices and the fabrication of index-guided quantum well heterostructure lasers by MeV oxygen ion implantation. 相似文献
48.
D. C. Coleman 《Fresenius' Journal of Analytical Chemistry》1997,357(2):209-213
In this article a brief overview of the World Wide Web (WWW) is given, with some examples of the kind of information and
services pertaining to analytical chemistry that can be found there. An existing WWW site that has been set up for analytical
chemists is used as a case in point. The article concludes with a brief look at some of the issues raised by publishing on
the Internet.
Received:15 January 1996 / Accepted: 28 January 1996 相似文献
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