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101.
U. Wollenberger B. Neumann K. Riedel F. W. Scheller 《Fresenius' Journal of Analytical Chemistry》1994,348(8-9):563-566
Biosensors employing a biocatalyst on a different level of integration have been developed for monitoring environmental pollution. These probes range from laboratory specimen to commercial detectors applied to analyzers. Recent developments on amperometric enzyme and microbial biosensors are presented here. A monoenzymatic bulk-type carbon electrode is described for biosensing organic hydroperoxides in aqueous solutions; peroxidase is immobilized within the electrode body and the direct electron transfer between electrode and enzyme is measured. Both, reversible and irreversible inhibitors of acetylcholinesterase have been quantified by using a kinetically controlled acetylcholine enzyme sequence electrode. The inhibitory effect of pesticides such as butoxycarboxime, dimethoate, and trichlorfon could be quantified within 6 min in molar concentrations. Different multi-enzyme electrodes have been developed for the determination of inorganic phosphate. These sensors represent examples of sequentially acting enzymes in combination with enzymatic analyte recycling. Using this type of amplification nanomolar concentrations can be measured. 相似文献
102.
V. Brüser S. Jakobs H. -H. Möbius U. Schönauer 《Fresenius' Journal of Analytical Chemistry》1994,349(8-9):684-687
Solid electrolyte cells for detecting NO2 with Ba(NO3)2 or Sr(NO3)2 partially replaced by -Al2O3 as solid electrolytes have been studied. The cell tension depends on the NO2- as well as on the NO-concentration. Investigations of the establishment of the NO2-NO-O2-equilibrium by the catalytic effects of the used electrode materials Pt and Au have shown that a decomposition of NO2 below 400°C cannot be expected.17th Communication on oxoanionic solid electrolytes and their possible applications; 16th Communication see Solid State Ionics 51:183–185 (1992)Extension of a part of the lecture of V. Brüser, S. Jakobs, H.-H. Möbius and U. Schönauer Galvanische NO2-Sensoren mit Nitrat-Festelektrolyten given in Feldberg, 3. 6. 1993 相似文献
103.
N. U. Baratov E. G. Mil'grom V. I. Vinogradova Ya. V. Rashkes M. S. Yunusov 《Chemistry of Natural Compounds》1994,29(6):760-766
The Pictet—Spengler condensation of bis--phenylethylbenzylamines with a central diphenyl ether group has given a new series of substituted bis-2-benzyltetrahydroisoquinolines the fragmentation of which under electron impact is determined by the properties that are characteristic for the monomeric compounds and is associated with the successive elimination of the two tetrahydroisoquinoline nuclei, the features of which depend on the mutual positions of the substituents in the diphenyl ether part of the molecule.Institute of the Chemistry of Plant Substances, Uzbekistan Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 854–861, November–December, 1993. 相似文献
104.
N. U. Baratov E. G. Mil'grom V. I. Vinogradov Ya. V. Rashkes M. S. Yunusov 《Chemistry of Natural Compounds》1994,29(6):748-759
Fourteen previously undescribed bases of the bis--phenylethylbenzylamine series with a central diphenyl ether group differing by the relative positions of the oxygen bridge and the -phenylethylbenzylamine substituent have been synthesized. The main directions of the fragmentationof these compounds under electron impact are competing single or successive processes of cleavage of the benzyl bonds, accompanied by the structuredependent transfer of hydrogen atoms.Institute of the Chemistry of Plant Substances, Uzbekistan Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii. No. 6, pp. 839–853, November–December, 1993. 相似文献
105.
K. Buse H. Hesse U. van Stevendaal S. Loheide D. Sabbert E. Krätzig 《Applied Physics A: Materials Science & Processing》1994,59(6):563-567
Photoconductivities and photovoltaic currents of ruthenium-doped KNbO3 are orders of magnitude larger than that of undoped and ion-doped crystals. KNbO3:Ru is very sensitive for holographic recording with red light and the photovoltaic current increases sublinearly with light intensity. 相似文献
106.
U. Meyer 《Communications in Mathematical Physics》1996,174(3):457-475
We give a systematic account of a component approach to the algebra of forms onq-Minkowski space, introducing the corresponding exterior derivative, Hodge star operator, coderivative, Laplace-Beltrami operator and Lie-derivative. Using this (braided) differential geometry, we then give a detailed exposition of theq-d'Alembert andq-Maxwell equation and discuss some of their non-trivial properties, such as for instance, plane wave solutions. For theq-Maxwell field, we also give aq-spinor analysis of theq-field strength tensor. 相似文献
107.
E. Bütkus J. C. Martins U. Berg 《Journal of inclusion phenomena and macrocyclic chemistry》1996,25(1-3):125-128
- and -cyclodextrins were found to form 1:1 inclusion complexes with 2,6- and 2,9-substituted bicyclo[3.3.1]nonanes. The binding constants and the structure of the complexes were estimated from titration studies and 2D ROESY experiments. 相似文献
108.
G. Krausch J. Colchero T. Detzel R. Fink B. Luckscheiter U. Wöhrmann G. Schatz 《Hyperfine Interactions》1993,78(1-4):295-301
Thin In films on Ge(100), Si(100) andSi(111) are investigated using Auger-electron spectroscopy (AES), atomic force microscopy (AFM) andperturbed -angular correlation (PAC) spectroscopy, respectively. The growth mode of the metal films is characterized by in situ AES measurements, indicating distinct differences between the different substrate surfaces. Additional AFM investigations are used to monitor the film topography at higher metal coverage. Finally, the local crystalline structure of the films is studied by the PAC technique. 相似文献
109.
The property of self-adjointness of the operatorQ =a
+ +a
- in three types ofq-oscillator algebras is considered. Spectral measures and generalized eigenfunctions ofQ are found in the cases when this operator is bounded. Generalized eigenvectors are expressed in terms ofq-Hermite polynomials. If the operatorQ is unbounded, then its closure
is not self-adjoint. However, in this case,
admits self-adjoint extensions. Deficiency subspaces are one-dimensional. These subspaces are explicitly found. 相似文献
110.
We show that classical chaotic scattering has experimentally measurable consequences for the quantum conductance of semiconductor microstructures. These include the existence of conductance fluctuations-a sensitivity of the conductance to either Fermi energy or magnetic field-and weak-localization-a change in the average conductance upon applying a magnetic field. We develop a semiclassical theory and present numerical results for these two effects in which we model the microstructures by billiards attached to leads. We find that the difference between chaotic and regular classical scattering produces a qualitative difference in the fluctuation spectrum and weak-localization lineshape of chaotic and nonchaotic structures. While the semiclassical theory within the diagonal approximation accounts well for the weak-localization lineshape and for the spectrum of the fluctuations, we uncover a surprising failure of the semiclassical diagonal-approximation theory in describing the magnitude of these quantum transport effects. 相似文献