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  • Articles  (28)
  • Chemistry  (28)
  • Wiley-Blackwell  (28)
  • Springer
  • 2010-2014
  • 1990-1994  (9)
  • 1980-1984  (10)
  • 1975-1979  (8)
  • 1965-1969  (1)
  • 1905-1909
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 8 (1994), S. 391-407 
    ISSN: 0886-9383
    Keywords: Neural networks ; Non-linear multivariate regression ; Pattern classification ; Kalman filter ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Finding methods for the optimization of weights in feedforward neural networks has become an ongoing developmental process in connectionist research. The current focus on finding new methods for the optimization of weights is mostly the result of the slow and unreliable convergence properties of the gradient descent optimization used in the original back-propagation algorithm. More accurate and computationally expensive second-order gradient methods have displaced earlier first-order gradient optimization of the network connection weights. The global, extended Kalman filter is among the most accurate and computationally expensive of these second-order weight optimization methods. The iterative, second-order nature of the filter results in a large number of calculations for each sweep of the training set. This can increase the training time dramatically when training is conducted with data sets that contain large numbers of training patterns. In this paper an adaptive variant of the global, extended Kalman filter that exhibits substantially improved convergence properties is presented and discussed. The adaptive mechanism permits more rapid convergence of network training by identifying data that contain redundant information and avoiding calculations based on this redundant information.
    Additional Material: 9 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 241-247 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, glass ; Quantitative analysis at 10-10g level ; Steroids in urine ; Amino acid fluorobutyrates (19 in 35 min) ; Installation of glass capillaries ; Connection to FM-ECD ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Glass capillary columns are ideal for analysis of urinary steroid profiles (i.e. the total steroid neutral fraction without prior separation into sub-groups).In this paper performance of both SCOT and wide-bore WCOT columns has been compared, resulting in no significant quantitative difference on urine extracts run as trimethylsilyl ether derivatives. However, because of increased efficiency the WB-WCOT column exhibited more sensitivity in measurement of small amounts of 11-ox-aetiocholanolone. Sensitivity of other steroids was greatly enhanced by use of either SCOT or WB-WCOT, leading to an almost tenfold increase over conventional packed columns (e.g. androsterone and aetiocholanolone 〈 40 μg per 24 h urine sample). A simple splitless injection system (based on a design of Dr. W. Greenaway, Oxford University) is presented.Experiments were also carried out using a SCOT column in conjunction with an FM-electron capture detector. Whilst efficiency was impaired due to the design of the detector, use of He (carrier) and N2 (make up gas) showed that several steroid derivatives could be easily measured at well below the 10-10 g level with much more rapid retention times than with a 1½m packed column. Highly successful separation of 19 amino acids (as fluoro-acyl derivatives) was achieved in 35 minutes using a SCOT (30 m) SP2100 column.
    Additional Material: 12 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 45 (1992), S. 1783-1788 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A procedure is described for preparing fairly uniform spheres of three different nylon polymers by phase separation. The mean diameter and polydisperse index were 5 μm and 1.056 for Griltex nylon, 5.7 μm and 1.046 for nylon 6/6, and 12.9 μm and 1.016 for nylon 6. The phase separation is done by taking a 1 wt % solution in a theta solvent above the theta temperature and cooling it rapidly. The spheres of the three nylons have various degrees of roughness. Formation of highly uniform particles during phase separation is discussed in a preliminary way. © 1992 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
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  • 4
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Composition of Mixtures of Hydrocarbons after BIRCH-Reduction of Substituted Benzenes and Acid Catalyzed Addition of Alcohols to Alkylsubstituted Cyclohexenes and Cyclohexa-1,4-dienes.10 different benzene hydrocarbons 1, indane, tetraline, anisol and phenol are reduced by sodium in liquid ammonia in the presence of methanol to the BIRCH products 2. The product mixture compositions are determined through capillary GLC. On storage at + 6°C some rearomatization of the 1,4-cyclohexadienes 2 occurs. Data of the 1H- and 13C-n.m.r. spectra and also mass spectra of the BIRCH 1,4-dienes 2 are given. For comparison 4-alkoxycyclohexenes 4 and 1-alkoxy-1-methylcyclohexanes 8 are prepared and spectroscopically characterized. Acid-catalyzed addition of alcohols to the 1,4-cyclohexadiene systems is a slow process and gives the 4-alkoxy-4-alkylcyclohex-1-enes (4) only in moderate yields up to 30 %. Most of the products are dimers 5 and also oligomers 6 of the parent hydrocarbons 2.
    Additional Material: 1 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 333 (1991), S. 447-453 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three Component Reactions. XX. Methoxymercuration of Cyclohexa-1,4-dienes.The methoxymercuration of several cyclohexa-1,4-dienes leads to insoluble mixtures of mono- and bismercuricompounds 2-4 and 5-7. After reduction with NaBH4/NaOH mixtures of methoxycyclohexenes and bismethoxycyclohexanes result. The result of capillary gaschromatographic analyses and n.m.r. spectra allow a semiquantitative evaluation of the reaction pathways.
    Additional Material: 1 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 332 (1990), S. 1088-1092 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1H.-N.M.R. Spectroscopic Evidence for the Complex Formation of Strontium Ions by Amido Podands
    Additional Material: 4 Ill.
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  • 7
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Plant/Operations Progress 3 (1984), S. 86-88 
    ISSN: 0278-4513
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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  • 9
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: N-Methyl-N-Diethoxyphosphorylamido Derivatives of Hexachlorocyclotriphosphazatriene. I. The Reaction of Hexachlorocyclotriphosphazatriene with Sodium N-Methylamidophosphoric Acid Diethyl Ester.The reaction of hexachlorocyclotriphosphazatriene with the sodium salt of 0, 0-diethyl-N-methylamido-phosphate in the molar ratios 1:1, 1:2, and 1:3 gives a mixture of partially substituted compounds. The N-methyl-N-diethoxyphosphorylamidoderivatives, N3P3Cl6-n[NCH3P(O)(OC2H5)]n (n = 1, 2, 3) were isolated in a pure form by preparative column chromatography. Compounds with a higher degree of substitution are not formed. The compounds are characterized by their molecular weights, elementary analysis, and TLC-Rf values.
    Notes: Die Reaktion von Hexachlorocyclotriphosphazatrien mit dem Natriumsalz des N-Methylamidophosphorsäurediäthylesters führt bei Raumtemperatur in den Molverhältnissen 1:1, 1:2 und 1:3 zu einem Gemisch partiell substituierter Verbindungen. Mit Hilfe der präparativen Säulenchromatographie konnten die N-Methyl-N-diäthoxyphosphorylamido-Derivate, N3P3Cl6-n[NCH3P(O)(OC2H5)2]n (n = 1, 2, 3); in reiner Form isoliert werden. Verbindungen höheren Substitutionsgrades wurden nicht erhalten. Die Verbindungen wurden durch ihre Molmassen, Elementaranalysen und die dünnschichtchromatographischen Rf-Werte charakterisiert und gesichert.
    Additional Material: 1 Ill.
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  • 10
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: N-Methyl-N-Diethoxyphosphorylamido Derivatives of Hexachlorocyclotriphosphazatriene. II. Ammonoloyses of N-Methyl-N-Diethoxyphosphorylamido-ChlorocyclotriphosphazatrienesMonokis-[N-methyl-N-diethroxyphosphorylamido]-pentachloro-cyclotriphospha-zatriene and 2, 4-bis-[N-methyl-N-diethoxyphosphorylamido]-2, 4, 6, 6-tetrachloro-cyclotriphosphazatriene react with gaseous ammonia at room temperature to the corresponding diamino compounds, N3P3CL4-n[NCH3P(O)(OC2H5)2]n(NH2)2, (n = 1, 2). Total Exchange of the chlorine in the N-Methyl-Ndiethoxyphosphorylamido-derivatives, N3P3CL6-n[NCH3P(O)(OC2H5)2]n, (n = a, 2, 3), takes place during the reaction with liquid ammonia. Aminophosphazenes of the type N3P3[NCH3P(O)(OC2H5)2]n(NH2)6-n, (n = 1, 2, 3), are formed. The described aminocyclotriphosphazatrienes are characterized by their melting points, elementary analyses, molecular weights and the TLC-Rf-values.
    Notes: Monokis-[N-methyl-N-diäthoxyphorylamido]-pentachloro-cyclotriphosphazatrien und 2, 4-Bis-[N-methyl-N-diäthoxyphosphorylamido]-2,4,6,6-tetrachlorocyclotriphosphazatrien reagieren mit gasförmigem Ammoniak bei Raumtemperatur zu den entsprechenden diaminoverbindungen, N3P3CL4-n[NCH3P(O)(OC2H5)2]n(NH2)2, (n = 1, 2). Vollständiger Austausch des Chlors in den N-Methyl-N-diäthoxyphosphorylamido-Derivaten, S3P3CL6-n[NCH3P(O). (OC2H5)2]n, (n = 1, 2, 3). findet bei der Umsetzung mit flüssigem ammonial Statt. Es werden dabei Aminocyclophosphazene des Typs N3P[NCH33P(O)(OC2H5)2]n(NH2)6-n, (n = 1. 2. 3) gebildet, Die beschriebenen Aminocyclophosphazatriene werden durch ihre Schmelzpunkte, Elementaranalysen, Molmassen und die dünnschichtchromatographischen Rf-Werte charakterisiert.
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