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1.
Werner Baltes Gloria Bochmann 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1987,184(3):179-186
Summary From model roastings of mixtures containing serine, threonine and sucrose about 350 volatile compounds were separated and identified by GC/MS. Among them there were more than 100 monocyclic furans, 13 furanones and 8 bicyclic furans, the mass spectra and retention indices of which are recorded. The most important mass spectrometric fragmentation pathways are described. Spectra obtained from roasting coffee under identical conditions are compared with the spectra from model roastings.
Dissertation Gloria Bochmann, TU Berlin 1984 相似文献
Modell-Reaktionen zur Röstaroma-BildungII. Die massenspektrometrische Identifizierung von Furanen und Furanonen aus der Reaktion von Serin und Threonin mit Saccharose unter den Bedingungen der Kaffeeröstung
Zusammenfassung Aus Modellröstungen von Gemischen aus Serin, Threonin und Saccharose unter den Bedingungen der Kaffeeröstung wurden etwa 350 flüchtige Verbindungen mittels GC/MS getrennt und identifiziert. Unter ihnen befanden sich über 100 monocyclische Furane und 13 Furanone sowie 8 bicyclische Furane, deren Massenspektren und Retentions-indices angegeben werden. Die wichtigsten massenspektrometrischen Fragmentierungswege werden beschrieben. -Die aus einer gleich behandelten Röstung von Rohkaffee erhaltenen Spektren werden mit denen der Modellröstungen verglichen.
Dissertation Gloria Bochmann, TU Berlin 1984 相似文献
2.
The design, fabrication, and characterization of thermally excited silicon oxide beam and bridge resonators by a modern industrial CMOS process combined with one additional maskless etching step is reported. The resonant frequencies, vibration amplitudes, and mode shapes of the devices are measured using a laser heterodyne interferometer. The acoustic transmitting and receiving sensitivities of the resonant structures in air are investigated in order to test their possible application as ultrasound transducers for proximity sensing. The experimental results are compared with finite element simulations using ANSYS 相似文献
3.
Lilli Heinrich und Werner Baltes 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1987,185(5):362-365
Zusammenfassung In zwei unterschiedlich gerösteten Robustakaffees und vier handelsüblichen Röstkaffees wurden die Phenole in bezug auf Struktur und Quantität untersucht. Nach speziellen Extraktions- und Reinigungsverfahren erfolgte die Identifizierung und Quantifizierung nach gaschromatographischer Trennung der Trimethylsilylether mit Hilfe der GC-MS-Kopplung. Die Gehalte der 35 identifizierten Phenole lagen in einem Bereich von unter 0,1 bis über 1000 mg/kg. 16 Phenole wurden erstmals im Kaffee nachgewiesen.
Herrn Dr. H. Lange zum 60. Geburtstag gewidmet 相似文献
Determination of phenols in coffee
Summary The structure and quantity of phenols, occurring in two different roastedRobusta coffees and in four samples of roast coffee, were investigated. Identification and quantification were carried out after special extraction procedures and clean-up methods by gas chromatography/mass spectrometry. The quantities of 35 phenols investigated ranged from below 0.1 mg/kg to more than 1000 mg/kg. Sixteen phenols were identified in coffee for the first time.
Herrn Dr. H. Lange zum 60. Geburtstag gewidmet 相似文献
4.
C Wilken W Baltes I Mehlitz R Tiebach R Weber 《Zeitschrift für Lebensmittel-Untersuchung und -Forschung》1985,180(6):496-497
A rapid procedure for the isolation and clean-up on a silica gel column is described for the determination of Ochratoxin A from pork kidneys. The detection limit is 0.3 microgram/kg. 相似文献
5.
Malcovati P. Azeredo Leme C. O'Leary P. Maloberti F. Baltes H. 《Solid-State Circuits, IEEE Journal of》1994,29(8):963-966
In this paper we present a new architecture for a smart sensor interface. It is based on an oversampled A/D converter associated with a small ROM containing calibration coefficients. The nonlinear function desired is obtained by piecewise linear interpolation between the values stored in the ROM, without any additional circuits. This solution has the advantage of high programming flexibility, long-term stability, and low area consumption. Moreover, it is suitable for co-integration with sensors because of its minimum analog content. A prototype was integrated in a CMOS 1.2-μm technology. Simulation and experimental results are reported together with a detailed theoretical analysis and some design guidelines 相似文献
6.
Riccobene C. Wachutka G. Burgler J. Baltes H. 《Electron Devices, IEEE Transactions on》1994,41(7):1136-1148
Dual collector magnetotransistors are magnetic-field-sensitive devices currently developed in several laboratories. Optimized sensor design is often attempted by trial and error rather than by established design rules. This motivated the present comprehensive study of the operation of magnetotransistors by accurate two-dimensional numerical simulations. We model vertical and lateral transistors as obtained by industrial IC technology on the basis of data provided by the chip manufacturer. We consider the entire device structure with the full, complex device geometry, and the physically proper boundary conditions. Our simulations reveal the details, controversial hitherto, of the operating principle of these devices. In particular we find that, in the case of the vertical transistor, it is essentially the emitter injection modulation effect which dominates the sensor response. In the case of the lateral transistor, the magnetic sensitivity is predominantly determined by minority-carrier deflection, though side effects are involved as well. By variation of the doping profile and the device geometry we derive rules for optimized magnetotransistor design 相似文献
7.
8.
Rheological Property and Stress Development during Drying of Tape-Cast Ceramic Layers 总被引:1,自引:0,他引:1
Jennifer A. Lewis Kimberly A. Blackman rea L. Ogden James A. Payne Lorraine F. Francis 《Journal of the American Ceramic Society》1996,79(12):3225-3234
Rheological property and stress development of tape-cast ceramic layers derived from nonaqueous alumina (A12 O3 )-poly(vinyl butyral) (PVB) suspensions were observed during drying. Casting suspensions exhibited strong shear-thinning behavior, with a low shear Newtonian plateau apparent viscosity >102 Pa. s. The apparent suspension viscosity displayed a power-law dependence on the A12 O3 volume fraction during the initial stage of drying (<30% solvent loss). Stress development, measured by a cantilever deflection method, and parallel weight loss measurements were performed during the drying of tape-cast layers and pure binder coatings. Maximum drying stresses (σmax ) of 1.37-0.77 MPa were observed for plasticized tapes cast at gap heights of 150-400 μm. In contrast, nonplasticized tapes of similar thickness displayed a more gradual stress increase, with σmax values approximately an order of magnitude higher than their plasticized counterparts. The stress histories of the corresponding binder coatings were quite similar to the tape-cast layers, albeit slightly lower σ max values were observed. Stresses decayed beyond σmax with a logarithmic time dependence to an almost constant value of 0.2-0.4 MPa for the plasticized tapes. Based on these observations, process methodologies have been offered to minimize stress development and retention in tape-cast ceramic layers 相似文献
9.
Older men and women have different life contexts as a function of differential longevity and socio-structural opportunities over the life course. The question is whether gender-related differences also occur in psychological and everyday functioning in older adults. Examined were 258 men and 258 women between the ages of 70 and 103 years (M = 85 years), participants in the Berlin Aging Study. Significant gender differences were observed in 13 of 28 aspects of personality, social relationships, everyday activity patterns, and reported well-being. Cluster analysis identified 11 subgroups whose profiles of life conditions and health and psychological functioning could be categorized as more or less desirable (functional). The relative risk of a less desirable profile was 1.6 times higher for women than for men. For older adults, gender as a variable carries differences in physical frailty and life conditions that likely have consequences for psychological functioning. 相似文献
10.
Helmut Tschiersky und Werner Baltes 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1989,189(2):132-137
Zusammenfassung Es wird über die Curiepunkt-Pyrolyse handelsüblicher Caramelzuckersirup-Proben und die Identifizerung von über 80 Pyrolysefragmenten durch kombinierte Capillargaschromatographie/ Massenspektrometrie berichtet. Mit dieser Methode sind die Proben untereinander and gegenüber Couleuren differenzierbar. Mittels Ultrafiltration wurden die Komponenten einer intensiv braunen Probe in Fraktionen unterschiedlicher Molekülmasse getrennt and nach Pyrolyse miteinander verglichen. In einer niedermolekularen Fraktion wurden nach Permethylierung Laevoglucosan, 1,6-Anhydro--d-glucofuranose, Trehalose, Cellobiose, Maltose, Isomaltose und Gentiobiose Bowie einige Difructosedianhydride nachgewiesen.
Investigations of caramel. Curiepoint pyrolysis of caramel syrups and other investigations of structure
Summary A report is given on the investigation of commercial caramel syrups by Curiepoint pyrolysis and the identification of more than 80 pyrolysis products by capillary gas chromatography mass spectrometry. This method enables the differentiation between different caramel syrups and, additionally, between caramel syrups and caramel colours. Compounds of different molecular masses have been examined in the same manner after they have been isolated from an intense brown caramel sample by ultrafiltration. In a fraction consisting of compounds with low molecular masses laevoglucosan, 1,6-anhydro--d-glucofuranose, trehalose, cellobiose, maltose, isomaltose, gentiobiose and some difructosedianhydrides were identified by GC/MS after permethylation.相似文献