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101.
Maurizio A. P. Mingardi 《光谱学快报》2013,46(6):141-147
In the past five years, a number of d6 complexes have been found to exhibit luminescence when excited by ultraviolet light. Such emission has been assigned to d-d transitions localized on the metal ion, to charge-transfer transitions, and to ligand localized transitions2,3. The specific kind of emission observed is thought to depend on which electronic level lies lowest in energy. 相似文献
102.
We developed a constituent quark-diquark model for the nucleon and its resonances using a harmonic oscillator potential for
the interaction. The effects due to relativistic kinetic energy correction are studied. Finally, charge form factor of the
model is calculated and compared with experimental data.
相似文献
103.
The pKa of 3',3",5',5"tetrabromo-m-cresolsulfonephtalein (Bromocresol Green) and o-cresolsulphonephtalein (Cresol Red) was spectrophotometrically measured in a water/AOT/isooctane microemulsion in the presence of a series of buffers carrying different charges at different water/surfactant ratios. Extended Principal Component Analysis was used for a precise determination of the apparent pKa and of the spectra of the acid and base forms of the dye. The apparent pKa of dyes in water-in-oil microemulsions depends on the charge of the acid and base forms of the buffers present in the water pool. Combination with multiple linear regression increases the precision. Results are discussed taking into account the profile of the electrostatic potential in the water pool and the possible partition of the indicator between the aqueous core and the surfactant. The pKa corrected for these effects are independent of w0 and are close to the value of the pKa in bulk water. On the basis of a tentative hypothesis it is possible to calculate the true pKa of the buffer in the pool. 相似文献
104.
More specific official methodology is needed to survey the illegal use of clenbuterol in animal production plus the synthesis of new compounds that currently elude routine analytical methods. The identification of a new adrenergic agonist, N1-(2-(4-amino-3,5-dichlorophenyl)-2-hydroxyethyl)-N1-isopropyl-propanamide (known as compound A) in animal feed has prompted studies to verify if the existing cleanup procedures developed for clenbuterol are really effective. This study considers the ion-exchange mechanism on cyanopropyl (CN), sulfonic cation exchange (SCX), mixed phase (MPH) (C8 + SCX), and nonendcapped C18 (C18NE) solid-phase extraction (SPE) columns. Results indicate that compound A (by contrast with clenbuterol) is not efficiently retained on the CN, SCX, and MPH SPE columns (recovery <10%). This finding thus leads to the development of a gas chromatography-tandem mass spectrometry procedure based on C18NE SPE that is able to purify both agonists from bovine livers spiked at 0.5, 1.0, and 2.0 ppb with a mean recovery of 93% for clenbuterol and 92% for compound A. 相似文献
105.
Georgakilas V Tagmatarchis N Pantarotto D Bianco A Briand JP Prato M 《Chemical communications (Cambridge, England)》2002,(24):3050-3051
High solubility of SWNTs and MWNTs in water is obtained by organic functionalisation; derivatisation with N-protected glycine is also easily achieved. 相似文献
106.
Tagmatarchis N Georgakilas V Prato M Shinohara H 《Chemical communications (Cambridge, England)》2002,(18):2010-2011
Electrophilic addition of chloroform to SWNTs followed by hydrolysis resulted in the addition of hydroxy groups to the surface of the nanotubes; further esterification with propionyl chloride led to the corresponding ester derivatives, which allowed us to identify their structure, also providing better solubility in organic solvents. 相似文献
107.
[reaction: see text] A new poly(ethylene glycol)-supported porphyrin has been prepared and its ability as a promoter in photooxidation reactions has been studied. The PEG-supported catalyst exhibits high activity, comparable to that of a nonanchored sensitizer, and it is easily removable by filtration from the reaction mixture. The polymer-bound porphyrin has been recycled up to six times with no loss of chemical and stereochemical efficiency. 相似文献
108.
109.
Maurizio Chicco 《Annali di Matematica Pura ed Applicata》1970,87(1):1-9
Summary I prove a generalized maximum principle and an evaluation of the first eingenvalue for linear second order elliptic partial
differential equations in divergence form with discontinuous coefficients.
Lavoro eseguito nell'ambito del Centro di ricerca di matematica e fisica teorica del Consiglio Nazionale delle Ricerche presso l'Università di Genova.
Entrata in Redazione il 14 luglio 1970. 相似文献
Lavoro eseguito nell'ambito del Centro di ricerca di matematica e fisica teorica del Consiglio Nazionale delle Ricerche presso l'Università di Genova.
Entrata in Redazione il 14 luglio 1970. 相似文献
110.