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991.
Kuo Hsiung Lee 《中国化学快报》2012,23(5):583-586
Two novel styryllactones,goniodilactone(1) and gonioheptenolactone(2),were isolated from the leaves of Goniothalamus cheliensis Hu.Their structures were determined on the basis of spectroscopic data as well as X-ray crystallography analysis. Compounds 1 and 2 exhibited significant cytotoxicities in a panel of human cancer cells,including DU-145,PC-3,MCF-7,A-549, KB and KBvin,with GI50S in the range of 1.29-4.56μg/mL. 相似文献
992.
To simplify the assessment method of soy protein isolate(SPI) functionalities,the viscosity and functionalities of commercial SPI products were studied.Viscosity value(y) increases with increasing concentration(x) and exhibits a highly significant correlation with the exponential equation y = a·ebx.The b values of products are gradually enhanced from dispersion,emulsion and injected to gel type.Products with low b values(<0.2),and high dispersivity were dispersion-type.Products having high b values (>0.4) and gel springiness were gel-type.The other products with centered b value(0.2-0.4),high solubility and emulsifying capacity were emulsion-type. 相似文献
993.
This paper investigates nonsingular terminal sliding mode control for a class of uncertain systems with nonlinear inputs and its application in chaos control. When some of the system states are finite-time stable, the nonlinear items that coupled with these states may come into zeros in other subsystems. This will simplify the stability analysis of the whole system greatly. Compared with the traditional finite-time stabilization design method, the introduction of the terminal sliding mode can reduce the input dimensions. Only one control input is requested to realize chaos control of the Liu system when unmatched uncertainties and input nonlinearity coexist. The parameter matrices in the TSM can be determined through the solution of LMIS. Simulation results are given to demonstrate the effectiveness of the proposed method. 相似文献
994.
995.
Yuming Yang Hua Lai Haitao Xu Chunyan Tao Hua Yang 《Journal of nanoparticle research》2010,12(1):217-225
In order to investigate the correlations of morphologies and optical properties, different morphologies of Eu-doped ZnO were
synthesized by different methods. Specifically, the structure of SiO2/ZnO:Eu nanoflower was synthesized for the first time and has not been reported previously. One percent was chosen as the
Eu doping concentration. The relations of the morphology, diameter, and uniformity with the PL intensity were examined. The
PL intensity of ZOE samples has a close relationship with the morphology. The PL intensity order of the different morphologies
of ZnO:Eu is as follows: nanorod arrays > thin film > nanospheres > nanoparticles > nanoflowers > nanorods. The PL intensity
of nanomaterials is larger, if the diameter of the nanomaterials is larger. However, the size of diameter is not the most
important reason. It was found that the sample uniformity plays a key role on ZnO:Eu PL intensity. ZnO:Eu with small particle
diameters may have strong photoluminescence intensity, if the nanoparticles are uniform. 相似文献
996.
997.
998.
A comparative study has been carried out between experimentally and naturally weathered pyrites. Both were found to share similar species of weathering products and a similar weathering mechanism. The weathering products could be divided into sulphur-bearing or iron-bearing groups. The sulphur-bearing group was comprised of sulphate, sulphite, thiosulphate, elemental sulphur, polysulphide, and mono-sulphide. The iron-bearing group was comprised of goethite, hematite or magnetite, and iron sulphate. The weathering structural profile was also similar for both types of weathering, being composed of a surficial layer and a transitional layer. The surficial layer was made up of both the sulphur-bearing and the iron-bearing products, while the transitional layer was comprised of goethite, and hematite or magnetite. The inward migration of the weathering interface was stimulated by the diffusion of oxygen and moisture. The oxygen was considered to preferably squeeze the iron to form goethite, and the ferric ions of goethite to have acted as a bridge for electron transfer between the oxygen and bulk S22− and Fe2+ of pyrite. 相似文献
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1000.