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991.
The paper studies the 1-D piston problem of the relativistic Euler equations when the speed of the piston is a perturbation
of a constant. A sequence of approximate solutions constructed by a modified Glimm scheme is proved to be convergent to the
weak solution (which includes a strong leading shock) to the piston problem. In particular, we give the precise estimates
on the reflection of the perturbed waves on the piston and the leading shock.
The paper is supported by the National Natural Science Foundation of China (Grant 10626034) and the Special Research Fund
for Selecting Excellent Young Teachers of the Universities in Shanghai. 相似文献
992.
993.
Simultaneous analysis of polygala acid,senegenin and 3,6′‐disinapoylsucrose in rat plasma by liquid chromatography–tandem mass spectrometry: application to a pharmacokinetic study after oral administration
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Longfei Lin Lei Yan Hui Zhang Xuechun Li Jin Zhang Haoran Dou Mingrui Shen Xingbin Yin Changhai Qu Jian Ni 《Biomedical chromatography : BMC》2014,28(5):594-600
A rapid and specific LC‐MS/MS method has been developed for the simultaneous analysis of polygala acid, senegenin and 3,6′‐disinapoylsucrose (DSS) in rat plasma. The method was applied to the pharmacokinetics studies of polygala acid, senegenin and DSS. The analysis was carried out on an Agilent Eclipse plus C18 reversed‐phase column (100 × 4.6 mm, 3.5 µm) by gradient elution with methanol and ammonia (0.01%, v/v). The flow rate was 0.4 mL/min. All analytes including internal standard (IS) were monitored by selected reaction monitoring with an electrospray ionization source. Linear responses were obtained for polygala acid and DSS ranging from 2.5 to 2000 ng/mL, and senegenin ranging from 5 to 2000 ng/mL. The intra‐ and inter‐day precisions (relative standard deviation) were <11.34 and 8.99%. The extraction recovery ranged from 70.89 ± 4.60 to 88.49 ± 3.26%, and that for the IS was 77.23 ± 3.68%. Stability studies showed that polygala acid, senegenin and DSS are stable during the preparation and analytical process. The validated method was successfully used to determine the concentration–time profiles of polygala acid, senegenin and DSS. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
994.
1 INTRODUCTIONCopper( ) displays a wide diversity in its structural chemistry,the copper co-ordination number ranging from two to four.Procedures to synthesize copper( )complexes are of greatinterestbecause of the diversity of products resulting from al-mostthe same methodology.Ithaslong been accepted thatcopper( ) complexesarediamagnetic and provide no optical absorption bands( no d- d transition isencountered) for a copper( ) ion with a d10 configuration and no electron spin reso-n… 相似文献
995.
Magnetite/poly (lactic acid) (PLA) composite microcapsules with controllable composition and magnetic property were synthesized
by a facile interfacial coprecipitation joint double emulsion–solvent evaporation process. In this method, the interfacial
coprecipitation was performed at the water-in-oil (W1/O) interface and the generated Fe3O4 nanoparticles were incorporated into PLA microcapsules simultaneously. The magnetite content of the resultant composite microcapsules
can be controlled as high as 38 wt.%. This novel method not only simplifies the fabrication process but also improves the
magnetic property of composite microcapsules. 相似文献
996.
Tiantian Yao Jing Lu Dacheng Li Jianmin Dou 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(4):364-367
A new tetranuclear mixed‐valence cobalt complex, namely di‐μ2‐azido‐diazidodiethanolbis{μ2‐2‐[(hydroxyimino)methyl]‐6‐methoxyphenolato}bis{μ3‐6‐methoxy‐2‐[(oxidoimino)methyl]phenolato}dicobalt(II)dicobalt(III) ethanol disolvate, [CoII2CoIII2(C8H7NO3)2(C8H8NO3)2(N3)4(C2H5OH)2]·2C2H5OH, has been synthesized by the reaction of Co(OAc)2·4H2O (OAc is acetate) with 3‐methoxysalicylaldoxime (H2mosao) in an ethanol solution. In the complex, the four Co cations all display distorted octahedral coordination environments and they are bridged by two κ2,κ1,κ1;μ3‐mosao2− ligands, two κ2,κ2;μ2‐Hmosao− ligands and two μ2‐N3− anions to form a tetranuclear [Co4N4O4] cluster. Adjacent clusters are connected through weak C—H...N and C—H...O interactions, resulting in a two‐dimensional supramolecular network parallel to the ac plane. The magnetic properties of the complex have also been studied. 相似文献
997.
Fu WW Shimizu N Dou DQ Takeda T Fu R Pei YH Chen YJ 《Chemical & pharmaceutical bulletin》2006,54(4):557-560
Five new triterpenoid saponins, platycoside H [3-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl-2beta,3beta,16alpha,23-tetrahydroxyolean-12-en-28-oic acid 28-O-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranoside], platycoside I [3-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl-2beta,3beta,16alpha,23-tetrahydroxyolean-12-en-28-oic acid 28-O-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranoside], platycoside J [3-O-beta-D-glucopyranosyl-2beta,3beta,16alpha,23-tetrahydroxyolean-12-en-28-oic acid 28-O-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranoside], platycoside K [3-O-beta-D-glucopyranosyl-(1-->3)-beta-D-glucopyranosyl-2beta,3beta,16alpha,23,24-pentahydroxyolean-12-en-28-oic acid], and platycoside L [3-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl-2beta,3beta,16alpha,23,24-pentahydroxyolean-12-en-28 oic acid], and three known triterpenoid saponins, platycoside F, platycoside B, and platycoside C, were isolated from the roots of Platycodon grandiflorum A. DC. Their chemical structures were elucidated on the basis of their spectral data and chemical evidence. 相似文献
998.
This paper is an EPR study on the generation of new 'magic blue' (MB) reagent containing bis{perfluoro[1-(2-fluorosulfonyl)ethoxy]ethyl}nitroxide 2 and perfluoro[1-nitroso-1-(2-fluorosulfonyl)ethoxy]ethane 3, both bearing chemically convertible terminal omega-fluorosulfonyl group -SO2F, and its H-abstraction reactions from arylalkanes, alcohols, aldehydes and polymers, leading to a large number of new fluorinated nitroxides (FN). 相似文献
999.
Song L Meng J Zhong J Liu L Dou X Liu D Zhao X Luo S Zhang Z Xiang Y Xu H Zhou W Wu Z Xie S 《Colloids and surfaces. B, Biointerfaces》2006,49(1):66-70
The adsorption behavior of human fibrinogen (Hfg) on single-walled carbon nanotube (SWNT) films was investigated using scanning electron microscopy (SEM) and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. It was shown in the SEM images that fibrinogen was adsorbed strongly on the surface of SWNT when the samples were incubated in the Hfg solutions for 10 min. The dependence of adsorption on the concentration of fibrinogen was also investigated and it was found that adsorption increased with increasing concentration. In order to further explore the adsorption of fibrinogen on SWNT surface, NEXAFS spectra were obtained at the N K-edge and the C K-edge. The results confirmed the conclusion regarding the dependence of adsorption on fibrinogen concentration. It is demonstrated that, due to its high sensitivity to the surface elements, NEXAFS spectroscopy is a powerful tool to investigate the adsorption of fibrinogen on SWNT films. 相似文献
1000.
In this paper, we introduce the notion of null flows via sequence entropy. We study the structure of minimal null flows and show that such a flow is almost automorphic and uniquely ergodic. Moreover, minimal null functions on
are defined and investigated. At the same time, we show that the set of almost automorphic flows strictly contain the set of minimal null flows which strictly contain the set of almost periodic flows. 相似文献