Two dimensional TLC determination of PAH in diluted automobile exhaust gases

A method is described for the determination of polycyclic aromatic hydrocarbons (PAH) in the diluted exhaust gas of diesel vehicles. Sampling is done by drawing off proportional streams from the dilution tunnel. The particulates deposited on filters are sublimed, and the sublimate is purified and prefractionated on silica gel. Further separation and quantitative determination of the PAH is performed by two dimensional TLC in conjunction with In situ fluorescence spectrometry. Results of theoretical considerations and experimental data on the distribution of the emitted PAH between particulate matter and the corresponding gas phase in diluted exhaust are presented. A modified Langmuir adsorption model is used to explain the effects of dilution ratio and sample temperature in the dilution tunnel. Comparison of the emission values for PAH obtained from diluted and undiluted exhaust shows good agreement. Furthermore, the PAH contents of the exhaust gas of several diesel-engined cars are also compared for various driving cycles.     

Die Abreißenergie von Teilchen aus der fluiden Phasengrenze

Ohne ZusammenfassungMit 1 AbbildungMitt.-Nr.: 317     

Berührungsloses Messen von Oberflächenspannung und prinzipielle Möglichkeiten zum Bestimmen des Randwinkels eines Fluides mit dem Interferenzmikroskop VELOMET-INTERPHAKO des VEB Carl Zeiss Jena

Zusammenfassung Mit Hilfe der InterferenzmikroskopeEPIVAL-Interphako oderVELOMET-Interphako können Oberflächenspannung und Randwinkel einer Flüssigkeit bestimmt werden, indem man die Neigungswinkel des Meniskusprofiles an zwei Punkten im horizontalen Abstand ₁, und ₂ von einer ebenen vertikalen Platte mißt. Die Methode und ihre Genauigkeit werden beschrieben und Testbeispiele für die Oberflächenspannung angegeben.

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Summary The surface tension and contact angle of a liquid can be determined by means of the interference microscopesEPIVAL-Interphako orVELOMET-Interphako by measuring the angle of inclination of the meniscus profile at two points in the horizontal distance ₁, and ₂ from a flat vertical wall. The method and its accuracy are described and tests for the surface tension are given.

     

Investigation of the current-voltage characteristics of superconducting film structures

The current-voltage characteristics (CVC) of sandwich structures consisting of superconducting Pb(S) and normalconducting Ag(N) in the combination SNS, NSN and SN have been investigated with the current flow parallel to the phase boundaries. We observed step structures in the CVCs and their dependence on an external magnetic field and on the layer thickness of Pb and Ag in the temperature range between 1.5 K and 4.2 K. The experimental results are compared qualitatively with the behaviour of the CVCs calculated by Hansack and Kümmel¹⁰.     

Über die Wertgleichheit homogener Linearformen

Ohne ZusammenfassungFür die Anregung und Hinweise für die vorliegende Arbeit möchte ich Herrn Prof. Dr.H. J. Weinert danken.     

Lifetime measurements on excited states in100Rh

Lifetime measurements of three excited states in¹⁰⁰Rh populated by the decay of¹⁰⁰Pd have been carried out. A two parameter delayedγ-γ-coincidence experiment using an intrinsic Ge and a plastic scintillation detector resulted in the following values:T _1/2(32.72 keV,¹⁰⁰Rh)=(27.6 ±0.6) nsT _1/2(74.8keV,¹⁰⁰Rh)=(213.6±2) nsT _1/2(158.8 keV,¹⁰⁰Rh)<0.5 ns. For the levels at 32.72 keV and 158.8 keV no former values are known.     

In situ study of the thermoresponsive behavior of micropatterned hydrogel films by imaging ellipsometry

A patterned hydrogel was immobilized on a polymer substrate by low-pressure argon plasma treatment using a masking technique. The polymer sample showed a thermoresponsive aggregation behavior in the region of 35-37 degrees C. The micropatterned, thermoresponsive hydrogel film has been characterized with imaging ellipsometry. The characterization was carried out on the dry film as well as on a swollen sample in water. The thermoresponsive behavior was studied in deionized water by temperature-dependent measurements in a solid-liquid cell. Through imaging ellipsometry, it was possible to distinguish the different regions of interest on a micrometer scale and to follow the swelling of the hydrogel part as a function of the temperature. It was possible to visualize the swelling as 3D profiles of Delta at various temperatures. Long-term changes of the sample could also be detected, which cannot be picked up by conventional ellipsometry.