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131.
Summary Two new cyclodextrin (CD) derivatives, heptakis{2,6-di-O-pentyl-3-O-[3′-(2″-chloro-4″,5″-dioxylmethene)-phenyl-5′-iso-oxazolylmethyl]}-β-CD
(CD I) and heptakis{2,6-di-O-methyl-3-O-[3′-(2″-chloro)-phenyl-5′-iso-oxazolylmethyl]}-β-CD (CD II) were synthesized and coated
on fused-silica capillary columns. Their chromatographic characteristics, including column efficiency, polarity, selectivity
and phase transition were studied and compared with similar β-CD stationary phases. It was found that the heterocycle group
has a significant effect on the selectivity of the CD stationary phases. Both stationary phases can be successfully used to
separate many di- and trisubstituted benzene positional isomers and show stronger separation ability in separating low-polarity
benzene positional isomers than other β-CD stationary phases. 相似文献
132.
133.
134.
Gu Chaohao 《Letters in Mathematical Physics》1992,26(3):199-209
A class of integrable systems of nonlinear partial differential equations in the spacetime R
n+1
is introduced. Single and multi-soliton solutions are constructed by using the Darboux matrix method. It is proved that as t±, a k multi-soluton solution splits asymptotically into k single solitons. Moreover, the interaction between solitons is elastic if we consider their magnitudes only.The work is C. H. Gu supported by the Chinese National Program for fundamental research nonlinear science. 相似文献
135.
Shao-Chen Yang Qihuang Gong Zongju Xia Y. H. Zou Y. Q. Wu D. Qiang Y. L. Sun Z. N. Gu 《Applied physics. B, Lasers and optics》1992,55(1):51-53
The nonlinear third-order optical susceptibility of C70 in a toluene solution is measured for the first time by the method of degenerate four-wave mixing using 10 ns laser pulses at 1.06 m. The third-order susceptibility X
in
(3)
is 5.6×10–12 esu for a C70 toluene solution at a concentration of 0.476 g/l. The correspondent magnitude of the hyperpolarizability 1111 of the C70 molecule is 1.2×10–30 esu which is in a good agreement with the prediction given by the model of a free electron in a spherical box. 相似文献
136.
137.
138.
139.
A method for the determination of methylmercury (MeHg) fluxes across the air–water and air–soil interfaces was developed using an in situ chamber. The MeHg in the air coming out of the chamber was captured by a column containing sulfhydryl cotton fiber adsorbent. MeHg was then desorbed from the column by using 2 mol L–1 HCl. The MeHg in the effluent was extracted with benzene, and determined by gas chromatography with electron capture detection. Finally, the MeHg flux was calculated using the chamber. The method was applied to simulated experiments, and the results showed that the MeHg fluxes in the air–water system were higher than those in the air–soil–water system. The method was also successfully applied to the field measurements of an environment polluted by a chemical factory, and the results showed that the MeHg fluxes across the air–soil and air–water interfaces were 0.21–3.09 and 0.14–0.79 ng m–2 h–1, respectively. The method will be a useful tool in the environmental study of MeHg. 相似文献
140.
CuAl2O4 powder synthesis by sol-gel method and its photodegradation property under visible light irradiation 总被引:1,自引:0,他引:1
Jiang Yanyan Li Jinggang Sui Xiaotao Ning Guiling Wang Chengyu Gu Xiumei 《Journal of Sol-Gel Science and Technology》2007,42(1):41-45
Nanocrystalline spinel CuAl2O4 powders were prepared by sol-gel method from nitrate Cu(NO3)2·3H2O, Al(NO3)3·9H2O and complex C6H8O7·H2O. Sintering was carried out at 400, 500, 600, 700, 800°C respectively for 2 h in air. The XRD patterns started to appear
CuAl2O4 peaks after sintering of 500°C and consist of only CuAl2O4 peaks as spinel crystal after sintering of 700°C. The powders were analyzed by TEM and UV-vis diffuse reflectance spectrum
to be round, about 10–30 nm in size and Eg=1.77 eV. Photodegradation property of nanocrystalline CuAl2O4 powders was investigated by using methyl orange as model pollutant and mercury lamp (λ>400 nm) as energy source. The results
indicated that CuAl2O4 powders sintered at 700°C had the excellent visible photocatalytic property. Under the irradiation of visible light, methyl
orange could be degraded 97% in 120 min. 相似文献