Journal of Optimization Theory and Applications - Recent advancements in the sensor industry, smart metering systems and communication technology have led to interesting electricity consumption... 相似文献
Abstract New N-substituted 4-arylidene-isoquinoline-1,3-dione derivatives were obtained as one geometrical isomer by aldol condensation of the appropriate aldehyde and the corresponding N-substituted homophthalimides. The structural elucidation of compounds 3a–h was established by infrared and NMR spectroscopy including 1
Dimmock , J. R. ;
Wong , M. L. C.Bioactivities and potential uses in drug design of acyclic α,β-unsaturated ketones . Can. J. Pharm. Sci.1976 , 11 , 35 – 53 .[Web of Science ®], [Google Scholar]H, 13
Perjési , P. ;
Szabó , D. ;
Batta , G. ;
Földesi , A.The stereochemistry of reaction of 2-benzylidenecyclohexanone with dithiocarbamic acid . Tetrahedron Lett.1987 , 28 , 571 .[Google Scholar]C, CH CORR, and distortionless enhancement by polarization transfer measurements. Compounds 3d–h were evaluated for their antibacterial activity against some strains of bacteria using the disc diffusion method and microdilution tests. 相似文献
A series of 2,2′-(dihydropyrimidine-1,3(2H,4H)-diyldimethanediyl)bis(substituted-phenols) was synthesized using a Mannich-type reaction between the macrocyclic aminal 1,3,7,9,13,15,19,21-octaazapentacyclo[19.3.1.13,7.19,13.115,19]octacosane (OAPO) (1) and substituted phenols in basic media. These previously unreported compounds were separated from the reaction mixture by column chromatography in highly pure form with 25–75% yields. The most stable conformer was predicted using AM1-type semiempirical quantum chemical calculations. 相似文献
A series of nine borylated arylisoquinolines has been prepared with systematic variation in their electronic properties and their photophysical properties were investigated. The color of their fluorescence can be finely tuned by changing the properties of the aryl moiety, which is involved in internal‐charge‐transfer processes. For example, methoxy‐substituted compound 5 showed an intense green emission, whereas dimethylamino‐substituted compound 6 showed an orange‐red emission. These new fluorophores were tested for their potential as molecular switches with external ionic stimuli, such as protons and fluoride ions. On the one hand, protonation of the isoquinoline moiety led to fluorescence enhancement for compounds that showed weak charge transfer and fluorescence quenching for compounds that showed strong charge transfer. On the other hand, the formation of ate complexes with fluoride led to strong fluorescence quenching in all of the investigated cases. 相似文献
In this study, the feasibility of solid‐phase extraction combined with gas chromatography and mass spectrometry in tandem with partial least squares discriminant analysis was evaluated as a useful strategy to differentiate wines according to geographical origin (Azores, Canary and Madeira Islands) and types (white, red and fortified wine) based on their global volatile patterns. For this purpose, 34 monovarietal wines from these three wine grape‐growing regions were investigated, combining the high throughput extraction efficiency of the solid‐phase extraction procedure with the separation and identification ability. The partial least squares discriminant analysis results suggested that Madeira wines could be clearly discriminated from Azores and Canary wines. Madeira wines are mainly characterized by 2‐ethylhexan‐1‐ol, 3,5,5‐trimethylhexan‐1‐ol, ethyl 2‐methylbutanoate, ethyl dl ‐2‐hydroxycaproate, decanoic acid, 3‐methylbutanoic acid, and (E)‐whiskey lactone, whereas 3‐ethoxypropan‐1‐ol, 1‐octen‐3‐ol, (Z)‐3‐hexenyl butanoate, 4‐(methylthio)‐1‐butanol, ethyl 3‐hydroxybutanoate, isoamyl lactate, 4‐methylphenol, γ‐octalactone and 4‐(methylthio)‐1‐butanol, are mainly associated with Azores and Canary wines. The data obtained in this study revealed that solid‐phase extraction combined with gas chromatography and quadrupole mass spectrometry data and partial least squares discriminant analysis provides a suitable tool to discriminate wines, both in terms of geographical origin as well as wine type and vintage. 相似文献
The determination of 256 multiclass pesticides in lavandin essential oil has been performed by liquid chromatography–electrospray ionization tandem mass spectrometry using the scheduled selected reaction monitoring mode available on a quadrupole-linear ion trap mass spectrometer. With the aim of improving the limits of quantification (LOQs) of the target molecules, a sampling step based on evaporation of the essential oil under a nitrogen flow assisted by controlled heating was tested. The LOQs determined in this case were compared with the values obtained with the classic dilution preparation method. With sampling by dilution, 247 pesticides were detected and quantified at low concentration, with 74 % of the pesticides having LOQs of 10 μg L-1 or less. With the evaporation method, a global improvement of the LOQs was observed, with lower LOQs for 92 active substances and LOQs of 10 μg L-1 or less for 82.8 % of the pesticides. Almost twice as many active substances had an LOQ of 1 μg L-1 or less when the evaporation method was used. Some pesticides exhibited poor recovery or high variance caused by volatilization or degradation during the evaporation step. This behavior was evidenced by the case of thiophanate-methyl, which is degraded to carbendazim.
Figure
Sampling method by dilution or evaporation in the multiresidue determination of pesticides in essential oils by LC/MS 相似文献
Cellulose - A modified TEMPO-catalyzed oxidation of the solvent-exposed glucosyl units of cellulose to uronic acids, followed by carboxyl reduction with NaBD4 to 6-deutero- and... 相似文献
This paper describes the development of a new sensor based on an ionic organic film. The amphiphilic molecule, 4‐[(4‐decyloxyphenyl)‐ethynyl]‐1‐methylpyridinium iodide (10PyI), which has liquid‐crystalline properties, was synthesized and applied in the construction of a GCE/10PyI sensor. Analytical parameters for caffeic acid, repeatability (4.8 %), reproducibility (2.8 %), linearity (two ranges: 9.9×10?7 to 3.8×10?5 mol L?1 and 4.7×10?5 to 9.9×10?5 mol L?1) and detection limits (9.0×10?7 mol L?1 and 8.7×10?6 mol L?1), were determined. The method was successfully applied in the determination of total phenolic compounds (TPC) in mate herb extracts. 相似文献