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71.
72.
W. Gielsdorf 《Fresenius' Journal of Analytical Chemistry》1980,301(5):434-435
Ohne Zusammenfassung
Mass spectral findings in urine after ingestion of dihydrocodeine (Paracodin®) and pentazocine (Fortral®)相似文献
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A radial basis function neural network (RBFNN) method was developed for the first time to model the nonlinear calibration curves of four hexachlorocyclohexane (HCH) isomers, aiming to extend their working calibration ranges in gas chromatography-electron capture detector (GC-ECD). Other 14 methods, including seven parametric curve fitting methods, two nonparametric curve fitting methods, and five other artificial neural network (ANN) methods, were also developed and compared. Only the RBFNN method, with logarithm-transform and normalization operation on the calibration data, was able to model the nonlinear calibration curves of the four HCH isomers adequately. The RBFNN method accurately predicted the concentrations of HCH isomers within and out of the linear ranges in certified test samples. Furthermore, no significant difference (p > 0.05) was found between the results of HCH isomers concentrations in water samples calculated with RBFNN method and ordinary least squares (OLS) method (R2 > 0.9990). Conclusively, the working calibration ranges of the four HCH isomers were extended from 0.08-60 ng/ml to 0.08-1000 ng/ml without sacrificing accuracy and precision by means of RBFNN. The outstanding nonlinear modeling capability of RBFNN, along with its universal applicability to various problems as a “soft” modeling method, should make the method an appealing alternative to traditional modeling methods in the calibration analyses of various systems besides the GC-ECD. 相似文献
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《中国化学快报》1998,(10)
Wehavereportedtheeffectofovercrowdinginthemassspectfaofcondensedpolycyclicaromaticcompounds'-'.Themassdifferencebetweenamolecularionandthemostintensefragmentionintheionfamilyofthehighestvalencecorrespondstothenumberofovercrowdedhydrogenatomsdetachingfromtheparention,andtheirmasspatternsaredifferentwiththetypeofovercrowding,i.e.fjord-orcrab-likeovercrowding.Thehighabundanceofspecificfragmentionsat70Vwascorrelatedwiththeloweringoftheirappearanceenergies.Hereweinvestigatedthemassspectraandthemech… 相似文献
77.
The gas-phase ion-molecule reactions of pyridine and fluorine-containing compounds have been studied by the electron impact/Fourier transfer ion cyclotron resonance mass spectrometry (EI/FTICRMS). Comparing the reaction of the standard sample perfluorotributylamine (PFTBA), in the case of 3-oxa-5-iodo-octafluoropentylsulfonyl azide (ICF2CF2OCF2CF2SO2N3), a series of addition-elimination products and loss 28 from the expected adducts were obtained. Possible reaction mechanism was discussed, which was consistent with the results obtained in the condensed phase. These results demonstrated that EI/FTICRMS is a complementary technique for study of the organic reactions. 相似文献
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Eng‐Chi Wang Keng‐Shiang Huang Kuo‐Fan Lin Shing‐Ming Chen Li‐Fun Wang 《中国化学会会志》2003,50(6):1171-1176
The fragmental behavior of some monocyclic N‐aryl‐δ‐valerolactams in EI‐MS was studied. Their molecular ion peak, together with some characteristic fragments such as [M‐29]+, [M‐56]+?, [M‐69]+, and [M‐98]+, were always found in a series of N‐aryl‐δ‐valerolactams in EI‐MS spectra. Furthermore, the mechanism for the interpretation of each fragment is described. 相似文献
80.
Organic Light Emitting Diodes with Lithium Contained Alq3 as Electron Injection Layer 总被引:1,自引:0,他引:1
Zugang Liu * J. L. Pinto . Department of Materials University of Oxford Parks Road Oxford OX PF UK . Departamento de Física Universidade de Aveiro Aveiro Portuga 《高等学校化学研究》2002,18(2):121-123
IntroductionInorganiclightemittingdiode(OLED) ,somemetalswithlowworkfunction ,suchasalloyofmag nesiumandsilver(Mg∶Ag) [1] andaluminium[2 ] ,areusedastheelectroninjectioncathodes .InMg∶Agal loysilverisusedtoprotectmagnesiumfromthereac tionofmagnesiumwithoxygenand… 相似文献