This work developed a simple and sensitive method for simultaneous determination of three effective ingredients, atropine, scopolamine and anisodamine, in Flos daturae based on capillary electrophoresis coupled with electrochemiluminescence detection. b-Cyclodextrin was used as an additive to the running buffer for obtaining the absolute separation. The proposed method displayed the linear ranges from 0.2 to 100, 0.2 to 100 and 20 to 200 mM for anisodamine, atropine and scopolamine with correlation coefficients more than 0.99, respectively. This method showed the relative standard deviations less than 4% and 6% for detection of migration time and peak height, respectively, and was suitable for the determination of these tropane alkaloids in plants and valuable in clinical and biochemical laboratories for quality control.
Tin-based dichalcogenides such as SnS2 and SnSe2 have attracted wide attention due to their significant potential for the next-generation optoelectronic and photonic devices in nanotechnology. We investigate the nonlinear absorption of SnS2 and SnSe2 nanosheets using the Z-scan technique with nanosecond pulse and picosecond at 532 nm for the first time. Z-scan measurement reveals that SnS2 nanosheets dispersions exhibit reverse saturable absorption (RSA) behavior under different pulses, which is in contrast to the saturable absorption (SA) observed in the SnSe2 naosheets dispersions resulted from different band gaps. The nonlinear absorption coefficient (β) and the figures of merit (FOM) of SnS2 dispersed in ethanol with linear transmittances of 0.75 at input energy of 6.16 μJ in the nanosecond regime are 12.78×10-10 m/W and 8.71×10-11 esucm, respectively. As for SnSe2 nanosheet dispersions, β and FOM are-12.58×10-10 m/W and 11.98×10-11 esucm at the same input energy, respectively. The RSA behavior coupled to the smaller optical limiting threshold Fth (0.23 J/cm 2) proves SnS2 a promising 2D material for protecting sensitive optical components or eyes from laser-induced damage. The SA performance indicates SnSe2 nanosheets prospective candidates for high-performance nanoscale nanophotonic devices like optical switches.
The nonlinear absorption and nonlinear refractive properties of ZrSe nanoflakes were studied with a 6.5 ns pulse laser at 532 nm. Open-aperture Z-scan curves reveal that ZrSe nanoflakes have a strong reverse saturable absorption property, and close-aperture Z-scan curves show that ZrSe dispersions possess a positive nonlinear refractive index caused by self-focusing. The nonlinear absorption coefficient, the nonlinear refraction coefficient, and the figures of merit (FOM) of ZrSe dispersed in water with linear transmittances of 0.86 at input energy of 18 μJ are 6.35 × 10 m W 15.73 × 10 m W, and 10.09 × 10 esu · cm respectively. In addition, nonlinear optical (NLO) performance of ZrSe nanoflakes depends on organic solvent dispersions. ZrSe nanoflakes in water dispersions have the largest FOM of 10.27 × 10 esu · cm, while the FOM in ethanol dispersions is 5.41 × 10 esu · cm at the same input energy of 26.5 μJ. The optical limiting threshold F of ZrSe nanosheet is 2.2 J cm under picosecond laser pulse. The Results imply that ZrSe nanoflakes are an extraordinarily promising material for novel nanophotonic devices like optical limiters.
Due to the interaction with the support, KNO 3 loaded on zeolite NaY began to decompose near 513 K, much lower than when unsupported. Through a special redox process, moreover, KNO 3 can be mainly decomposed at 673 K while the release of NO x is suppressed by more than 90%. KNO 3 is widely used as an additive or promoter for enhancing the activity and/or selectivity of catalysts. Recently, novel solid bases have been derived from the KNO 3 supported on porous materials. Yamaguchi et al. observed an unusually high activity of KNO 3 /Al 2 O 3 in the isomerization of cis-but-2-ene at 273 K. 1 Zhu et al. reported the superbasicity of KNO 3 /Al 2 O 3 and KNO 3 /KL. 2,3 Through a comparison of KNO 3 dispersion of KNO 3 on Al 2 O 3 with that on zeolite NaY, they contributed the superbasic properties of KNO 3 /Al 2 O 3 to the several layers of K 2 O overlapped on the surface of alumina. 4 On the other hand, KNO 3 supported on ZrO 2 can also create superbasic sites with basic strength of H=26.5. 5 Before activation to decompose KNO 3 , these KNO 3 supported catalysts did not show any basicity, so that the contamination of CO 2 from the atmosphere can be avoided. Since these strong basic sites only formed in the in situ activation prior to reaction, they consequently retain high efficiency in the catalytic process. 1,4 There are two factors, however, which hinder the application of KNO 3 supported catalysts in industry. The first one is the high temperature needed to generate strong basic sites through decomposition of KNO 3 , e.g. 873 K for KNO 3 /Al 2 O 3 and over 873 K for KNO 3 /NaY, 4 since this thermal process cannot be applied to some zeolites with a large surface area but with low stability. The second one is the release of NO x (x 2), which is well known to be harmful to the environment. It is necessary to seek a new method for the decomposition of KNO 3 at a lower temperature with a smaller release of NO x , and in this paper we report using the redox method for decomposing KNO 3 supported on zeolites.
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