1,481 research outputs found
4-Chlorophenyl 2-oxo-2H-chromene-3-carboxylate
In title compound, C16H9ClO4, the coumarin ring system is approximately planar [maximum deviation = 0.056 (1) Å] and is oriented with respect to the benzene ring at an angle of 22.60 (7)°. Intermolecular C—H⋯O hydrogen bonding is present in the crystal
Single application on iris localization technology in excimer laser for astigmatism
AIM:To discuss the single application on iris localization technology in excimer laser for the treatment of astigmatism. <p>METHODS:Totally 203 cases(406 eyes)of laser <i>in situ</i> keratomileusis(LASIK)in the treatment of compound myopic astigmatism patients were operated from November 2011 to November 2012 in our hospital. They were divided into two groups. One was observation group using iris localization and the other was control group using routine operation. Patients in the observation group of 100 cases(200 eyes), aged 18-43 years old, spherical diopter was -1.25 to -8.75D, astigmatism was -1.0 to -3.25D. In control group, 103 patients(206 eyes), aged 19-44 years old, spherical diopter was -1.75-9.50D, astigmatism was -1.0 to -3.25D. The patients in the observation group before the application of WaveScan aberrometer check for iris image, spherical lens, cylindrical lens and astigmatism axis data operation, only single application of iris location, without using wavefront aberration guided technology, laser cutting patterns for conventional LASIK model, spherical, cylindrical mirror and astigmatism axis data source to preoperative wavefront aberration results. The control group received routine LASIK. It was applicated comprehensive optometry optometry respectively to examine astigmatism and axial, based on the computer analysis during the preoperative, 1wk after the operation, and 6mo. Analysis of using SPSS 17 statistical software, it was independent-sample <i>t</i> test between the two groups of residual astigmatism and astigmatism axis. <p>RESULTS:Postoperative residual astigmatism, the observation group was significantly better than the control group. Astigmatism axial measurement after operation, the observation group was significantly less than that of the control group. Postoperative visual acuity at 6mo, the observation group was better than that of the control group. The difference was statistically significant. <p>CONCLUSION: For patients who cannot complete the wavefront aberration guided treatment of astigmatism, can separate the application of wavefront aberration analyzer automatic iris recognition technology to improve precision of astigmatism treatment, give full play to advanced technical performance of equipment, which has good application value
Numerical simulation of the through process of aerospace titanium alloy casting filling, solidification, and hot isostatic pressing
Production of proton-rich nuclei around Z=84-90 in fusion-evaporation reactions
Within the framework of the dinuclear system model, production cross sections
of proton-rich nuclei with charged numbers of Z=84-90 are investigated
systematically. Possible combinations with the Si, S, Ar
bombarding the target nuclides Ho, Tm, Yb,
Lu, Hf and Ta are analyzed thoroughly. The
optimal excitation energies and evaporation channels are proposed to produce
the proton-rich nuclei. The systems are feasible to be constructed in
experiments. It is found that the neutron shell closure of N=126 is of
importance during the evaporation of neutrons. The experimental excitation
functions in the Ar induced reactions can be nicely reproduced. The
charged particle evaporation is comparable with neutrons in cooling the excited
proton-rich nuclei, in particular for the channels with and proton
evaporation. The production cross section increases with the mass asymmetry of
colliding systems because of the decrease of the inner fusion barrier. The
channels with pure neutron evaporation depend on the isotopic targets. But it
is different for the channels with charged particles and more sensitive to the
odd-even effect.Comment: 15 pages, 10 figures. arXiv admin note: text overlap with
arXiv:0803.1117, arXiv:0707.258
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