Femtosecond x-ray and visible pulses were used to probe structural and electronic dynamics during an optically driven, solid-solid phase transition in VO(2). For high interband electronic excitation ...(approximately 5 x 10(21) cm(-3)), a subpicosecond transformation into the high-T, rutile phase of the material is observed, simultaneous with an insulator-to-metal transition. The fast time scale observed suggests that, in this regime, the structural transition may not be thermally initiated.
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Laser plasma accelerators have produced femtosecond electron bunches with a relative energy spread ranging from 100% to a few percent. Simulations indicate that the measured energy spread can be ...dominated by a correlated spread, with the slice spread significantly lower. Measurements of coherent optical transition radiation are presented for broad-energy-spread beams with laser-induced density and momentum modulations. The long-range (meter-scale) observation of coherent optical transition radiation indicates that the slice energy spread is below the percent level to preserve the modulations.
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The purpose of this study was to provide an account of the 5-year experience we have gained using holmium:yttrium-aluminium-garnet (Ho:YAG) lasertripsy in the treatment of ureteral stones. ...One-hundred thirty-seven transurethral ureterolithotripsies were performed in 131 patients. A Ho:YAG laser device, fibres with diameters of 360 and 550 mum, a video camera as well as semi-rigid and flexible ureterorenoscopes were used. Results showed that the direct success rates-which meant stone-free ureters on the first post-operative day-in the upper, middle and lower ureters were 84.6, 88.7 and 94.8%, respectively. The final success rates--which meant stone-free ureters 4 weeks after the operation without a second intervention--were 84.6, 96.7 and 96.7%, respectively. The pulsatile Ho:YAG laser beam fragmented all kinds of stones easily. No ureteral stricture or reflux was identified during the follow-up period. The advantages of Ho lasertripsy outweighed its disadvantages. Based on our experience, the Ho:YAG laser is one of the most effective and safest energy sources in the treatment of ureteral calculi.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
We report laser plasma accelerators have produced femtosecond electron bunches with a relative energy spread ranging from 100% to a few percent. Simulations indicate that the measured energy spread ...can be dominated by a correlated spread, with the slice spread significantly lower. Measurements of coherent optical transition radiation are presented for broad-energy-spread beams with laser-induced density and momentum modulations. The long-range (meter-scale) observation of coherent optical transition radiation indicates that the slice energy spread is below the percent level to preserve the modulations.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
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