5,152 research outputs found
Insulator-to-metal phase transition in Yb-based Kondo insulators
The periodic Anderson lattice model for the crystalline electric field
(CEF)split 4f quartet states is used to describe the Yb-based Kondo
insulators/semiconductors. In the slave-boson mean-field approximation, we
derive the hybridized quasiparticle bands, and find that decreasing the
hybridization difference of the two CEF quartets may induce an
insulator-to-metal phase transition. The resulting metallic phase has a hole
and an electron Fermi pockets. Such a phase transition may be realized
experimentally by applying pressure, reducing the difference in hybridization
of the two CEF quartets.Comment: 5 pages, 3 figure
Clinical observation of phacoemulsification in patients with previous trabeculectomy
AIM: To observe the clinical effect of transparent corneal incision phacoemulsification in cataract patients who had undergone different kinds of glaucoma filtration surgeries.<p>METHODS: Totally 43 cases(50 eyes), in which 23 patients with primary angle-closure glaucoma(group A, 26 eyes)and 20 patients with primary open angle glaucoma(group B, 24 eyes), all had undergone glaucoma filtration surgery for more than 6 months. Visual acuity, intraocular pressure, slit lamp, gonioscope, corneal endothelial cell counts, <i>etc</i>., were done before surgery.And transparent corneal incision phacoemulsification combined with artificial lens implantation operation were preformed, postoperative follow-up of 3 to 12 months, visual acuity, intraocular pressure, corneal endothelial cell counts and vision field, <i>etc</i>. were observed and recorded.<p>RESULTS: The visual acuity of 50 eyes(100%)increased with different degree postoperatively, 41 eyes(82%)with postoperative visual acuity ≥0.3; average preoperative intraocular pressure: group A 18.08±5.08mmHg(1mmHg=0.133kpa), group B 14.48±3.52mmHg; Postoperative follow-up average intraocular pressure: group A 13.65±3.51mmHg, group B 14.28±3.41 mmHg, intraocular pressure changed significantly pre and post-operation in group A(<i>P</i><0.05), there was no significant difference between pre and post-operation in group B(<i>P</i>>0.05); Postoperative intraocular pressure of 1 eye in group A and 3 eyes in group B rose within three days post-operation, the intraocular pressure fluctuated between 21-33mmHg, with drug therapy and drug withdral when intraocular pressure epistrophy; Intraocular pressure was stable in the follow-up process.Corneal endothelial cell density: pre-operation group A was 2 293.57±352.24(cells/mm<sup>2</sup>), group B 2 658.14±458.69(cells/mm<sup>2</sup>), post- operation group A 2 175.95±379.16(cells/mm<sup>2</sup>), group B 2 442.97±477.30(cells/mm<sup>2</sup>), cell loss rate: 5.13% in group A, and 8.10% in group B. Postoperative visual acuity was related to vision field damage in patients, the more visual field damage, the longer the duration. <p>CONCLUSION: Visual function restore is stable in transparent corneal incision phacoemulsification in cataract patients who underwent glaucoma filtration surgeries; the intraocular pressure can be controlled effectively, and can further reduce the intraocular pressure of angle-closure glaucoma. Preoperative comprehensive evaluation of the affected eye and appropriate technique selection are benefit to the improvement of operation effect and the reduction of complications
Search for charmonium and XYZ states in at BESIII
Within the framework of nonrelativistic quantum chromodynamics, we study the
production of charmonium states in at BESIII
with (n=1, 2, 3, and 4), (n=1, 2, and 3), and
(n=1 and 2). The radiative and relativistic corrections are
calculated to next-to-leading order for and wave states. We then argue
that the search for states such as , , ,
and in at BESIII may help clarify the nature
of these states. BESIII can search states through two body process
, where decay to , , or
. This result may be useful in identifying the nature of
states. For completeness, the production of charmonium in at B factories is also discussed.Comment: Comments and suggestions are welcome. References are update
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