ABSTRACT
This publisher's note contains corrections to Opt. Lett.40, 5224 (2015).OPLEDP0146-959210.1364/OL.40.005224.
ABSTRACT
The self-absorption effect is one of the main bottlenecks for the laser-induced breakdown spectroscopy (LIBS) technique. In this Letter, LIBS assisted by laser-stimulated absorption (LSA-LIBS) is proposed to solve this problem. The process of LSA in self-absorption reduction is discussed and confirmed. The serious self-absorption phenomena of spectral lines (K, Mn, and Al) were not observed in LSA-LIBS. The full width at half-maximum (FWHM) of K, Mn, and Al was reduced by about 58%, 25%, and 52%, respectively. The results demonstrate the capability of this approach to self-absorption reduction in the LIBS technique.
ABSTRACT
The concentrations of vanadium and titanium elements in the steel samples were quantitatively analyzed by Laser-induced breakdown spectroscopy technique in the present paper. The lines of V (VI: 440.85 nm) and Ti (Ti I: 334.19 nm) were chosen as the quantitative analysis spectral lines, while spectral line of Fe (Fe I: 438.35 nm) was chosen as the internal calibration line due to it being the matrix element. Then the calibration curves of V and Ti elements were established with basic calibration method and internal calibration method respectively to quantitatively analyze the concentrations of vanadium and titanium elements in steel. The experimental results showed that the fitting correlation coefficient (R2) of vanadium and titanium elements are 0.9875 and 0.9909 when using basic calibration method, and their maximum relative errors of measurement are 11.09% and 4% respectively; while the fitting correlation coefficient (R2) of vanadium and titanium elements reachs 0.9952 and 0.9921 respectively when using internal calibration method, at the same time, the relative errors of measurement for vanadium and titanium elements were decreased to be lower than 4%. The results of this study demonstrated that the concentration measurement of vanadium and titanium elements in the steel was more suitable with internal calibration method in laser-induced breakdown spectroscopy.
ABSTRACT
OBJECTIVE: To evaluate the correlation of collateral circulation with prognosis in patients with acute cerebral infarction. METHODS: A total of 260 patients with acute ischemic stroke within 1 week of symptom onset underwent digital subtraction angiogram (DSA). The National Institutes of Health Stroke Scale (NIHSS) scores were obtained at admission. And the Modified Rankin scores (mRS) were assessed at a 3-month follow-up. The follow-up data were acquired through clinic visits or telephone interviews. RESULTS: Among them, 86 were found to have intra- or extra-cranial culprit artery severe stenosis or occlusion. And 36 (75.00%) in 48 patients had collateral arterial circulation while 11 (28.64%) in 38 patients posterior circulation. There were statistical differences in the NIHSS scores at admission and favorite clinical outcome (mRS ≤ 2) at 3-month follow-up for patients with and without collateral circulation. CONCLUSION: DSA is the golden standard for the assessment of collateral circulation in patients with severe cerebral artery stenosis or occlusion. The prognosis is better in stroke patients with collateral circulation.
