TE011腔使用扁平样品管提高水溶液样品ESR波谱灵敏度的研究

实验表明,在TE₀₁₁模式园柱形腔中,不但可以使用扁平样品管测量水溶液样品的ESR波谱,而且获得好的腔品质因子Q和高品质的ESR信号。所观察到的信号高度,是使用最佳尺寸毛细管样品时最大信号高度的3.2倍;又是在具有波导尺寸的TE₁₀₂腔中使用扁平样品管时所获得信号高度的3倍。本文对此作了定性的理论分析。     

Symplectic geometry and geometric quantization on supermanifold withU numbers

The usual theory of supermanifold is extended to the case that contains (anti)commuting variable pairs with oppositeU numbers. The symplectic geometry and geometric quantization on such a special manifold are discussed in detail. As applications, the BRST system with finite dimensional first class constraints and bosonic strings are investigated systematically.     

Boundary layer solutions for some nonlinear elastic membrane problems

Summary The method of matched asymptotic expansions is used to describe finite axisymmetric deformations of two thin elastic membrane problems: a circular membrane with a small radial traction at the edge, an annular membrane with a small circular hole at the center. In both problems, the surface load is assumed to be an axial pressure. There is a boundary layer at the outer edge in the first problem, and at the hole in the second problem.

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Zusammenfassung Mit Hilfe der in der singulären Störungsrechnung benutzten Methode einer inneren und äußeren asymptotischen Entwicklung werden endliche, axialsymmetrische Deformationen bei zwei Membranproblemen beschrieben: eine dünne elastische Kreismembran mit kleiner radialer Zugspannung am Rande, und eine Kreisringmembran mit einem kleinen konzentrischen Loch. In beiden Problemen wird die Belastung als ein axial gerichteter Oberflächendruck angenommen. Im ersten Problem zeigt die Lösung am äußeren Rand Grenzschichtverhalten, welches im zweiten Problem am Lochrand vorliegt.

     

Preparation and characterization of branched and linear sulfonated poly(ether ketone sulfone) proton exchange membranes for fuel cell applications

Branched sulfonated poly(ether ketone sulfone)s (Br‐SPEKS) were prepared with bisphenol A, bis(4‐fluorophenyl)sulfone, 3,3′‐disodiumsulfonyl‐4,4′‐difluorobenzophenone, and THPE (1,1,1‐tris‐p‐hydroxyphenylethane), respectively, at 180 °C using potassium carbonate in NMP (N‐methylpyrrolidinone). THPE, as a branching agent, was used with 0.4 mol % of bisphenol A to synthesize branched copolymers. Copolymers containing 10–50 mol % disulfonated units were cast from dimethylsulfoxide solutions to form films. Linear sulfonated poly(ether ketone sulfone)s (SPEKS) were also synthesized without THPE. The films were converted from the salt to acid forms with dilute hydrochloric acid. A series of copolymers were studied by Fourier transform infrared, ¹H‐NMR spectroscopy, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Sorption experiments were conducted to observe the interaction of sulfonated polymers with water and methanol. The ion‐exchange capacity (IEC), a measure of proton conductivity, was evaluated. The synthesized Br‐SPEKS and SPEKS membranes exhibit conductivities (25 °C) from 1.04 × 10^?3 to 4.32 × 10^?3 S/cm, water swell from 20.18 to 62.35%, IEC from 0.24 to 0.83 mequiv/g, and methanol diffusion coefficients from 3.2 × 10^?7 to 4.7 × 10^?7 cm²/S at 25 °C. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1792–1799, 2008     

Isolation and Characterization of C-phycocyanin from Spirulina Platensis

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Studies on ζ-Potential of Positive Sol of Magnesium Aluminum Hydroxide

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｅｌｅｃｔｒｉｃｐｏｔｅｎｔｉａｌａｔｔｈｅｓｈｅａｒｐｌａｎｅｂｅｔｗｅｅｎｔｈｅｃｈａｒｇｅｄｓｕｒｆａｃｅａｎｄｅｌｅｃｔｒｏｌｙｔｅｓｏｌｕｔｉｏｎｉｓｃａｌｅｄζ－ｐｏｔｅｎｔｉａｌ．Ｗｈｅｎζ＝０，ｔｈｅｐＨ...     

Identification of metabolites of Danggui Buxue Tang in rat urine by liquid chromatography coupled with electrospray ionization time‐of‐flight mass spectrometry

A method coupling liquid chromatography with electrospray ionization time‐of‐flight mass spectrometry (LC/ESI‐TOF/MS) has been developed for rapid and sensitive analysis of rat urinary metabolite profile of Danggui Buxue Tang (DBT), a well‐known Chinese herbal formula. After oral administration of DBT, urine samples were collected during 0–24 h, and then pretreated by solid‐phase extraction. A total of 68 compounds including 13 parent compounds and 55 metabolites were detected in the drug‐containing urines compared with blank urines. The total analytical time was less than 20 min. Metabolites of DBT were identified using dynamic adjustment of the fragmentor voltage to produce structure‐relevant fragment ions. By using this approach, the mass accuracy of precursor and fragment ions was typically within ±5 ppm of the theoretical values, and enabled the identification of 43 metabolites including 27 isoflavanoid and 16 phthalide metabolites. Our results indicated that glucuronidation and sulfation were the major metabolic pathways of isoflavonoids, while glutathione conjugation, glucuronidation and sulfation were the main metabolic pathways of phthalides. No saponin‐related metabolites were detected. The results of the present study provided important structural information relating to the metabolism of DBT. Furthermore, this work demonstrated the potential of the LC/ESI‐TOF/MS approach for identification of metabolites from Chinese herbal medicines in urine. Copyright © 2009 John Wiley & Sons, Ltd.     

Simultaneous quantification of five major constituents in stems of Dracaena plants and related medicinal preparations from China and Vietnam by HPLC–DAD

A high‐performance liquid chromatographic (HPLC) method was developed for the simultaneous quantification of five major bioactive constituents in the stems of resiniferous Dracaena plants from China and Vietnam, as well as those in the related traditional Chinese medicinal preparations. A diode array detector with the wavelength of 330 nm was used to monitor resveratrol, 7,4′‐dihydroxyflavone and pterostilbene, while loureirin A and loureirin B were monitored at 280 nm. The five constituents were separated on an Agela SB C₁₈ column by gradient elution using 0.008% (v/v) formic acid solution (A) and acetonitrile (B) as the mobile phase. The validation of the method included recovery, linearity, accuracy and precision (intra‐ and inter‐day variation). The range of recoveries of this method was 98.1–104.9%, with all the constituents showing good linearity (r² > 0.9999). The accuracy and precision were satisfactory, with the overall intra‐ and inter‐day variation being less than 4%. The present method has been successfully applied for the determination of all five constituents in 21 related herbal samples including 10 D. cochinchinensis stem samples, seven D. cambodiana stem samples and four purchased medicinal preparations. The contents of these constituents were analyzed using principal component analysis, which can efficiently identify raw herb of Dracaena from different sources. The study may be considered helpful to the quality control of Dracena plants and its medicinal preparations. Copyright © 2009 John Wiley & Sons, Ltd.