Über die anwendbarkeit der mikrotorsionswaage 1700 zur mikrogrammanalyse

The high precision of the Sartorius micro-balance 1700 with its load capacity of 2 g permits a weighing precision of ± 10 μg, which is the value of a half scale-division; by means of the classical “statistical weighing method”, an increased precision of ±1 μg is attainable. This accuracy is, in the investigated range, independent of the load up to 1.5 g.     

Beitrag zur Anwendung der Gel-Chromatographie in der Rückstandsanalyse,insbesondere am Beispiel der Bestimmung von Triazophos und Pyrazophos

The clean-up of the ethylacetate extracts of 31 common crops with the aid of liquid chromatography on polysterene gel is described. With a few exceptions, e.g. onions, the pesticide residue can be determined directly in the eluate gas-chromatographically using the electron capture or the flame photometric detector.     

Resonant light scattering by optical solitons

We consider the process of light scattering by optical solitons in a planar waveguide with homogeneous and inhomogeneous refractive index cores. We observe resonant reflection (Fano resonances) as well as resonant transmission of light by optical solitons. All resonant effects can be controlled in experiment by changing the soliton intensity.     

Discrete breathers in Fermi-Pasta-Ulam lattices

We study the properties of spatially localized and time-periodic excitations--discrete breathers--in Fermi-Pasta-Ulam (FPU) chains. We provide a detailed analysis of their spatial profiles and stability properties. We especially demonstrate that the Page mode is linearly stable for symmetric FPU potentials. A resonant interaction between a localized and delocalized perturbations causes weak but finite strength instabilities for asymmetric FPU potentials. This interaction induces Fano resonances for plane waves scattered by the breather. Finally we analyze the interplay between energy thresholds for breathers in the presence of strongly asymmetric FPU potentials and the corresponding profiles of the low-frequency limit of breather families.     

Kinetic theory of bridge processes

The detailed consideration of the kinetic aspect of the bridge process has allowed us to correctly write a kinetic equation beginning with knowledge of system microparameters. The solution of the equations makes it possible to elucidate the character of the relaxation process and to determine its typical constants as functions of those microparameters. Particular attention was given to kinetics in the presence of polaron effects. In this case the standard perturbation theory applied to derive the kinetic equations is not valid. The solutions obtained for this case are different both in the form of correlation functions and in the character of the interaction taken into account.     

Calculation of the components of the photoelastic effect in alkali-halide crystals

Calculations are made to determine the contribution of Lorentz-field and Coulomb-field anisotropy in alkali-halide crystals to the photoelastic coefficients p₁₁–p₁₂ and p₄₄ as well as to the piezopolarizability constants K, K, K_x, K_z, and K₀. These calculations are based on Mueller's theory of the photoelastic effect, with data on iron polarizability and photoelastic coefficients. The applicability of Mueller' s theory to the complete series of alkali-halide crystals is analyzed. Criteria are established for the ionicity of bonds in these crystals.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 28–34, December, 1975.     

Measurement and Modeling of Water Vapor Adsorption on Zeolite 4A—Equilibria and Kinetics

The adsorption of water vapor on Zeolite 4A has been analyzed. Both equilibrium and kinetics are examined. The equilibrium is measured with a static-volumetric method in a wide range of partial pressure and temperature and is modeled by several conventional approaches and a new type isotherm model, which fitted the obtained data best. Kinetics are determined by measuring breakthrough curves. The breakthrough curves are matched by a detailed model based on a modified linear driving force (LDF) approximation for the mass exchange. An analytic expression for the corresponding LDF-coefficient is designed in order to describe its dependency on water concentration, temperature and pressure. For the practical range of operating conditions the dependency on concentration can be described by the nonlinearity of the adsorption isotherm. The dependency on temperature and pressure corresponds to that of molecular diffusion. The presented data and models for equilibria and kinetics provide a basis for modeling and optimizing air-drying processes containing Zeolite 4A.An erratum to this article can be found at     

Zur densitometrischen quantitativen Bestimmung am Mikrochromatogramm

Zusammenfassung Es wird über die Anwendung des Chromoscan-Doppelstrahlendensitometers zur quantitativen Bestimmung von Aminosäuren berichtet. Die Trennung und Identifizierung erfolgt mittels eindimensionaler Arbeitstechnik am Mikrochromatogramm. Bei geringstem Aufwand an Geräten und Reagentien wird eine schnelle Auftrennung der Komponenten erreicht. Nach Überführung in die Ninhydrinkomplexe erfolgt die direktphotometrische Bestimmung der einzelnen Komponenten. Anhand von Analysenbeispielen werden die Möglichkeiten dieser Methode aufgezeigt und vergleichende Betrachtungen zur quantitativen Bestimmung der Aminosäuren nach Elution der Ninhydronkomplexe und photometrischer Messung mittels eines empfindlichen Mikrophotometers angestellt.

---

Summary A report is given on the application of the Chromoscan double-ray densitometer for the quantitative determination of amino-acids. The amino-acids are separated and identified by means of the unidimensional technique on the micro-chromatogram. Thus the separation of the different components is carried out whith the least consumption of reagents and equipment. After having been converted to the ninhydrin complexes, the single components are determined direct-photometrically. Several examples are given to show the possibilities of application of this method. Besides, it is compared with the quantitative determination of the amino-acids by means of elution of the ninhydrin complexes and photometric measurements with a sensitive microphotometer.