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1.
Jocelyne Hellou Raymond J. Andersen Shahin Rafii Edward Arnold Jon Clardy 《Tetrahedron letters》1981,22(42):4173-4176
The structure of luteone (), a twenty three carbon terpenoid, has been solved by performing a single crystal x-ray analysis on a 3,4-dinitrophenylhydrazone derivative. 相似文献
2.
Three new Δ3-norcycloartene triterpenoids, with differing side chain functionalities, have been isolated from the tropical green alga collected in Guam. The structures of these new compounds were secured by x-ray crystallography and by chemical interconversion. 相似文献
3.
Kazem D. Safa Mohammad Shahrivar Shahin Tofangdarzadeh Akbar Hassanpour 《Tetrahedron》2007,63(15):3189-3194
Metalation of (HSiMe2)3CH with lithium diisopropylamide (LDA) in THF gives (HSiMe2)3CLi, which reacts with ethylene oxide, propylene oxide, 1,2-epoxy butane, 1,2-epoxy pentane, 1,2-epoxy hexane, and epichlorohydrin to give the corresponding 1-oxa-2-silacyclopentane derivatives. Then, glycidylmethacrylate (GM) random copolymers with styrene (St) (in a 1:1 and 1:3 mol ratio) were synthesized by solution free radical polymerization at 70(±1) °C using α,α′-azobis(isobutyronitrile) (AIBN) as an initiator. Both types of copolymers were treated with (HSiMe2)3CLi to give new modified copolymers. The reaction of (HSiMe2)3CLi with epoxides on the side chains of the copolymers does not lead to intramolecular nucleophilic attack contrary to simple epoxides. All the products have been characterized by spectroscopic techniques. 相似文献
4.
A very simple, selective and sensitive spectrophotometric method for the determination of dodecyl benzene sulfonate (DBS) has been investigated. In this method, the ion pair of DBS and methylene blue was adsorbed onto plasticized poly(vinylchloride) membrane as a solid phase extraction medium. The absorbance of the blue membrane was measured at 660nm against a blank membrane using a spectrophotometer. The influence of type and amount of plasticizer, pH, concentration of methylene blue, temperature of sample solution and time of extraction on the absorbance of membrane was studied. Linear calibration was obtained over a concentration range of 0.1 to 6.5µgmL–1 of DBS. The method was applied to the determination of DBS in different commercial detergents. The precision and accuracy of the method is comparable with the conventional standard method. This method is cost-effective, and the use of organic solvent such as chloroform is completely eliminated. 相似文献
5.
Issa Yavari Loghman Moradi Farough Nasiri Hoorieh Djahaniani 《Monatshefte für Chemie / Chemical Monthly》2005,36(9):1757-1761
The regioselective reaction of N1-benzyl-N2-(4-nitrophenyl)ethanediamide with dialkyl acetylenedicarboxylates or alkyl propiolates in the presence of triphenylphosphine
leads to dialkyl 4-benzylamino-1-(4-nitrophenyl)-5-oxo-2,5-dihydro-1H-pyrrole-2,3-dicarboxylates or alkyl 4-benzylamino-1-(4-nitrophenyl)-2-oxo-5-pyrrolidinecarboxylates in good yields. 相似文献
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9.
Mwsleh Mwhmadi Mehdi Kamali Jamal Rashidiani Omid Rezai Kaveh Moradi Ashkan Faridi Khadijeh Eskandari 《Journal of Cluster Science》2014,25(6):1577-1587
NiO and CuO nanostructures were synthesized successfully via simple and fast microwave approach. Olive oil was chose as surfactant for stabilizing nanostructures. Different parameters such as microwave time and power and olive oil concentration were investigated on product size and morphology. The products were characterized with X-ray diffraction pattern, scanning electron microscopy, transmission electron microscopy and energy dispersive spectrometry analysis. 相似文献
10.
Amirali Sadeqi Shapour Moradi Kourosh Heidari Shirazi 《Mathematical and Computer Modelling of Dynamical Systems: Methods, Tools and Applications in Engineering and Related Sciences》2020,26(1):55-79
ABSTRACTThe scope of output-only/blind identification is restricted to stochastic/statistical processes, but for the first time in this study, the detectability conditions for general output-only subspace identification are investigated. This aids the range of input sources to be extended in a much realistic manner, beyond the only stochastic inputs. For this purpose, the subspace framework is assigned to make a connection between the output signal contents and the LTI system order. A few substantial hypotheses and algebraic statements are propounded affirming the sufficiency of the genuine output sequences for the identification purpose. This can be perceived as the cornerstone of state-space model reconstruction. In order to consolidate the notions according to reality, several examples are studied and examined for different input classes with stochastic disturbance. 相似文献