Effect of rGO on polymer-dispersed liquid crystal fabricated by RAFT polymerisation

In this study, we demonstrated that doping polymer matrix with a small amount of reduced graphene oxide (rGO) component (0.05–0.2%) had significant influence on the polymerisation kinetics and electro-optical performances of polymer-dispersed liquid crystal films (PDLCs) fabricated with macro reversible addition-fragmentation chain transfer agents. The effects of rGO content were studied in terms of morphology, compound viscosity, polymer conductivity, polymerisation kinetics and driving voltage of PDLCs. The results exhibited that higher rGO content increased the compound viscosity and the entire process proceeded slowly. Furthermore, the addition of rGO increased the polymer conductivity and local electric field, and reduced the saturation voltage as well as the threshold voltage from 27.3 to 19.5 V and 13.2 to 6.41 V, respectively.     

Identification of metabolites in WZS‐miniature pig urine after oral administration of Danshen decoction by HPLC coupled with diode array detection with electrospray ionization tandem ion trap and time‐of‐flight mass spectrometry

Danshen (DS) is a widely used traditional Chinese medicine for treating cardiovascular and cerebrovascular diseases. A simple, rapid and sensitive method was developed for identification of the in vivo metabolites in urine of WZS‐miniature pigs after oral administration of DS decoction by HPLC coupled with diode array detection with electrospray ionization tandem ion trap and time‐of‐flight mass spectrometry. This method has been successfully applied to simultaneous identification of 50 compounds (including 11 new ones) in pig urine. In addition, one new compound, (3‐hydroxyphenyl) crylic acid glycine methyl ester (C1), along with eight known ones were first isolated by column chromatography and identified by spectroscopic means, including 1D/2DNMR and mass spectrometry, as reference substances. Ten phenolic compounds (protocatechuic aldehyde, protocatechuic acid, caffeic acid, danshensu, ferulic acid, isoferulic acid, rosmarinic acid and salvianolic acid A/B/D) were found to be the main absorbed original constituents of DS decoction, which underwent the metabolic reactions of glucuronidation, sulfation, methylation, hydrogenation and glycine conjugation in vivo. In conclusion, the developed method is applicable to the analysis and identification of constituents in biological matrices after administration of DS decoction. Copyright © 2012 John Wiley & Sons, Ltd.     

不同尺寸的NdFeB稀土永磁体热退磁行为研究

针对不同类型及不同尺寸的两类NdFeB永磁体分别研究了它们随温度变化的热退磁行为。采用样品的整体剩余磁通来表征热退磁过程中磁体性能的变化。结果表明,Pc较小的永磁体温度稳定性较差,随温度的升高,样品的剩余磁通迅速衰减;Pc<<0.1的普通型永磁体,温度为100℃时样品的剩余磁通损失超过60%。高矫顽力型永磁体比普通型磁体具有更优越的温度稳定性和高温性能。温度升高主要导致磁体矫顽力降低,140℃时普通型磁体的矫顽力降低约80%,而高矫顽力型磁体的矫顽力只降低了约20%。     

Strong ergodicity of the regime-switching diffusion processes

We provide criteria for the strong ergodicity of regime-switching diffusion processes. Our conditions are imposed on the coefficients of the processes. Particularly, we show that for regime-switching diffusions on the half line, if the corresponding diffusion on each fixed environment is strongly ergodic, then the regime-switching diffusion is strongly ergodic as well, which does not depend on the changing rate of the environment. Moreover, the converse is not always true, which is shown by an example. For transience, recurrence and positive recurrence, there is no such good consistency [R. Pinsky and M. Scheutzow, Some remarks and examples concerning the transience and recurrence of random diffusions, Ann. Inst. Henri. Poincaré 28 (1992) 519–536].     

Micromechanical analysis of damage in saturated quasi brittle materials

In this paper, we propose a micromechanical analysis of damage and related inelastic deformation in saturated porous quasi brittle materials. The materials are weakened by randomly distributed microcracks and saturated by interstitial fluid with drained and undrained conditions. The emphasis is put on the closed cracks under compression-dominated stresses. The material damage is related to the frictional sliding on crack surface and described by a local scalar variable. The effective properties of the materials are determined using a linear homogenization approach, based on the extension of Eshelby’s inclusion solution to penny shaped cracks. The inelastic behavior induced by microcracks is described in the framework of the irreversible thermodynamics. As an original contribution, the potential energy of the saturated materials weakened by closed frictional microcracks is determined and formulated as a sum of an elastic part and a plastic part, the latter entirely induced by frictional sliding of microcracks. The influence of fluid pressure is accounted for in the friction criterion through the concept of local effective stress at microcracks. We show that the Biot’s effective stress controls the evolution of total strain while the local Terzaghi’s effective stress controls the evolution of plastic strain. Further, the frictional sliding between crack lips generates volumetric dilatancy and reduction in fluid pressure. Applications of the proposed model to typical brittle rocks are presented with comparisons between numerical results and experimental data in both drained and undrained triaxial tests.     

Global synchronization of weighted cellular neural network with time-varying coupling delays

New sufficient conditions are derived to guarantee the global synchronization of the weighted cellular neural network with multiple time delays. Based on Lyapunov theory, this paper proposes an adaptive feedback controlling method to identify the exact topology of a rather general weighted cellular neural network system with time-varying delays and then considers the synchronization of the neural network with different nodes dynamics. The parameters in this paper are very few and experiments show that the methods presented in this paper are of high application in global synchronization.     

Effect of F-doping on the properties of LiFePO4-x/3Fx/C cathode materials via wet mechanical agitation-assisted high-temperature ball milling method

Journal of Solid State Electrochemistry - LiFePO4-x/3Fx/C (x = 0, 0.03, 0.06, 0.09) were obtained via wet mechanical agitation-assisted high-temperature ball milling method. XRD, SEM,...