ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 2 (1988), S. 247-263 
    ISSN: 0886-9383
    Keywords: Calibration ; Tensor ; Multivariate ; PCR ; MLR ; PLS ; Regression ; Multidimensional arrays ; Order ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Many analytical instruments now produce one-, two- or n-dimensional arrays of data that must be used for the analysis of samples. An integrated approach to linear calibration of such instruments is presented from a tensorial point of view. The data produced by these instruments are seen as the components of a first-, second- or nth-order tensor respectively. In this first paper, concepts of linear multivariate calibration are developed in the framework of first-order tensors, and it is shown that the problem of calibration is equivalent to finding the contravariant vector corresponding to the analyte being calibrated. A model of the subspace spanned by the variance in the calibration must be built to compute the contravarian vectors. It is shown that the only difference between methods such as least squares, principal components regression, latent root regression, ridge regression and partial least squres resides in the choice of the model.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 2 (1988), S. 265-280 
    ISSN: 0886-9383
    Keywords: Calibration ; Tensor ; Multivariate ; Order ; Regression ; Generalized rank annihilation ; GRAM ; Multi order ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tensorial calibration provides a useful approach to calibration in general. For calibration of instruments that produce two-dimensional (second-order) arrays of data per sample, tensoial concepts are as natural a way of solving the calibration problem as vectorial concepts are for the multivariate problem. Similarly, for third- and higher-order data, the tensorial description of calibration is also useful. This paper introduces second-order calibration from a tensorial point of view. Univariate, multivariate and bilinear approaches to calibration are presented. The generalized rank annihilation method (GRAM) is described from the tensorial perspective, and it is shown that GRAM is equivalent to finding a second-order tensorial base that spans both tensors (calibration and unknown) with respective diagonal component matrices. GRAM uses a single calibration sample for multicomponent analysis even in the presence of interference. Second-order bilinear calibration is extended to multiple calibration samples where the effect of collinearities is reduced.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 3 (1989), S. 493-498 
    ISSN: 0886-9383
    Keywords: Rank annihilation ; Generalized rank annihilation method ; Generalized eigenproblem ; Calibration ; Spectral interferents ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An improved algorithm for the generalized rank annihilation method (GRAM) is presented. GRAM is a method for multicomponent calibration using two-dimensional instruments, such as GC-MS. In this paper an orthonormal base is first computed and used to project the calibration and unknown sample response matrices into a lower-dimensional subspace. The resulting generalized eigenproblem is then solved using the QZ algorithm. The result of these improvements is that GRAM is computationally more stable, particularly in the case where the calibration sample contains chemical constituents not present in the unknown sample and the unknown contains constituents not present in the calibration (the most general case).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 23 (1985), S. 185-191 
    ISSN: 0749-1581
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Very low power irradiation of suitable narrow peaks in the proton frequency range generated NOE enhancement in neighbouring quaternary carbons, positioned two bonds from the irradiated protons. Subsequent FID acquisition under normal broad band decoupling yielded the NOE-containing FID, which, after subtraction of the unperturbed broad band decoupled FID (devoid of NOE), gave the final NOE difference FID to which only the carbons undergoing NOE enhancement had contributed. Fourier transformation of the latter gave the NOE difference spectrum, usually a one- or two-peak spectrum. This technique proved particularly useful for polysubstituted aromatic rings.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 23 (1985), S. 879-881 
    ISSN: 0749-1581
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 80 MHz 1H NMR and 20 MHz 13C NMR spectra of eleven substited benzalazines (subsituenst: α-methyl, α,α′-dimethyl, 2-hydroxy, 2,2′-dihydroxy, 4-n-octyloxy, 4,4′-di-n-octyloxy) possessing mesogenic acivity have been assigned using a variety of one-dimensional techniques. These include homonuclear NOE measurements, selective heteronuclear 13C{1H} NOE difference spectroscopy, singlefrequency off-resonance decoupling, spin - echo multiplicity sorting (SEFT) and long-range heteronuclear coupling constant determintion via both gated decoupling and selective excitation (DANTE).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 0749-1581
    Keywords: Indirect heteronuclear NOEs ; 1H-19F-1H and 1H-19F-13C systems ; Three-spin effects ; Anomalous intensity effects ; Conformational analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Indirect nuclear Overhauser enhancements through 19F have been determined for the three-spin systems 1H-19F-1H and 1H-19F-13C by steady-state presaturation of the appropriate proton, and applied to the conformational analysis of 5-bromo-2-fluoro-4-nitroacetanilide. The 1H NOE difference spectra at 400 MHz showed antiphase doublets for protons undergoing simultaneous dipolar relaxation with, and scalar coupling to, 19F. Similarly, in the 13C selective NOE difference spectrum at 100 MHz, the two lines of the fluorine-bearing carbon showed negative enhancement factors of different magnitude on presaturation of the appropriate proton. The use of these anomalous intensity effects in conformational analysis is illustrated.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 0749-1581
    Keywords: 13C NMR ; Heteronuclear ; NOE ; Conformation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 20.15 MHz 13C NMR spectra of five 3,6,9-trioxanthracenes and four 3,6-dioxa-9-thianthracenes have been assigned using a variety of one-dimensional techniques. These include spin-echo multiplicity sorting (SEFT), long-range heteronuclear coupling constant determination via gated decoupling and selective heteronuclear 13C{1H} NOE difference spectroscopy. The axial position of substituents on C-10 has been demonstrated.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 0749-1581
    Keywords: Heteronuclear NOE ; Selective heteronuclear 13C{1H} NOE ; Indirect Negative NOE ; 13C—1H—{1H} three-spin effects ; Coumarins ; 2(1H)-Quinolones ; Benzo[b]furans ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 80 MHz 1H NMR and 20 MHz 13C NMR spectra of five 4-methylcoumarins, six 4-methyl-2(1H)-quinolones and nine 3-methylbenzo[b]furans, including six new compounds, were fully assigned. Homonuclear 1H{1H} NOEs and selective heteronuclear 13C{1H} NOEs were measured after low-power pre-saturation of the methyl protons. Indirect, negative heteronuclear NOE enhancements were found in suitable three-spin systems of the 13C—1H—{1H} type, and their magnitude was found to be dependent on ring size. The first examples of indirect, heteronuclear NOE enhancements on non-protonated carbons are described.
    Additional Material: 12 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 23 (1985), S. 1072-1075 
    ISSN: 0749-1581
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The technique previously described as two-bond heteronuclear selective NOE difference was improved to yield quantitative data on NOE enhancement factors by recording separately the unperturbed and the perturbed FIDs. In this way the E and Z stereoisomers of 4(α-arylethylidene)-2-phenyl-5(4H)-oxazolones were easily distinguished. The latter showed positive NOE ehancements on quaternary carbons placed two, three and four bonds away from the irradiated methyl protons, as well as a negative NOE on a nearby protonated carbon.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 0749-1581
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thirty-seven halogeno-substituted 2- and 3-methyl-(or halogenomethyl)-benzo [b]thiophenes, including 17 new compounds, were prepared. The constitution of 14 of these was confirmed by full analysis (LAOCOON) of their 80 MHz1HNMR spectra and by 1H{1H} NOE measurements. In this way a by-product from the preparation of 4- and 6-bromo-3-bromomethylbenzo[b]thiophenes was shown conclusively to be 5-bromo-3-bromomethylbenzo[b]thiophene. The 3-substituted benzo[b]thiophenes showed greater NOE enhancement factors at H-4 than at H-2 when the 3-methyl or halogenomethyl substituent was irradiated.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...