Originalarbeiten Autoradiographische Untersuchungen zum Verschleiß von Stahl

Bei Verschleißuntersuchungen mit einer Stift-Scheibe-Apparalur, in der an Stelle des Stifles eine neutronenaktivierte Stahlkugel eingesetzt wird, wird in unserem Laboratorium außer Radioaktivitätsmessungen mit Zählgeräten auch die Autoradiographie angewandt. Dazu wird der Schmierstoff mit dem losen Verschleiß abgewaschen und der festhaftende (adhäsive) Verschleiß durch Kontaktautoradiographie abgebildet. Die notwendigen Expositionszeiten liegen meist bei 2 bis 3 Wochen, wobei im allgemeinen TF 14-Filmmaterial verwendet wird.

Experimentelle Beispiele werden gezeigt und diskutiert. Mit neutronenaktivierten Stahlkugdn verschiedener Abklingzeit wurde durch Verghieh von Radioaktivitätsmessungen mit Zählgeräten und Autoradiographie gezeigt, daß die Schwärzung vorwiegend von der ß-Strahlung der entstandenen Radionuklide herrührt.     

Gamma- und Röntgendetektoren aus hochohmigem neutronendotiertem n-Silizium

Aus geeignetem p-Silizium mit kleinen Borverteilungsschwankungen konnte hochohmiges n-Silizium mittels Neutronendotierung hergestellt werden. Dieses n-Silizium diente zur Herstellung von Detektorstrukturen mit implantierten Kontakten. Diese Detektoren sind für den Nachweis von Photonenstrahlung geeignet.

An Hand der beschriebenen phyiskalischen Grundlagen der Neutronendotierung und der Detektorparameter werden die Wege zur Verbesserung der spektrometrischen Eigenschaften von Detektoren aus neutronendotiertem Silizium diskutiert.     

The Construction of an Apparatus for the Evaluation of Abrasive Properties of Dentifrice Using Radioisotopes

Construction of an original apparatus (brushing machine) designed to test the abrasiveness of dentifrice is described. The principle of the procedure employed consists in neutron activation of a human tooth subsequently brushed with the dentifrice under study in standard conditions. The radioactivity level of the dentifrice indicates the relative degree of its abrasive properties.

The design of the apparatus meets the radiation safety requirements. Its working parameters crucial to the wearing process (i.e. the pressure applied to the tooth specimen, the total number, frequency and amplitude of the brushing strokes) can be programmed precisely.     

The Wearing of Bearings Studied by Means of High Resolution Microautoradiography)

The high resolution microautoradiography has been originally developed as a sensitive method for the examination of cell structures and cell metabolism. The present state of autoradiography in biology can be denoted as an autoradiography of the molecules within the cells. The employment of microautoradiography is restricted not only to the field of the cell or molecular biolgy, but after a modification of the procedure it can be applied in quite different branches.

In our case microautoradiography has been used as a complementary method in running studies of the wearing out of the rolling bearings (Klime? 1975) for a localization of adhesive wear²) on the different parts of the bearings. If high resolution microautoradiography is used there is a presumption of exact identification of the contact path in the contact surface with qualitative differentiation of rolling and/or sliding contact. These facts give rise to the qualitatively new pieces of knowledge.     

Radionuclide‐Activated Nanomaterials and Their Biomedical Applications

Radio‐nanomedicine, or the use of radiolabeled nanoparticles in nuclear medicine, has attracted much attention in the last few decades. Since the discovery of Cerenkov radiation and its employment in Cerenkov luminescence imaging, the combination of nanomaterials and Cerenkov radiation emitters has been revolutionizing the way nanomaterials are perceived in the field: from simple inert carriers of radioactivity to activatable nanomaterials for both diagnostic and therapeutic applications. Herein, we provide a comprehensive review on the types of nanomaterials that have been used to interact with Cerenkov radiation and the gamma and beta scintillation of radionuclides, as well as on their biological applications.     

Radiography with Solid State Nuclear Track Detectors

The investigation of localisation is counted among the typical and important applications of nuclear track recorders. In this paper, after a comparison of the most important features of nuclear track recorders a system of their applications is given. On the grounds of information obtained from the tracks, eight groups of applications can be distinguished. One of them represents the four geometrical situations of the different types of radiography.

Taking radiography into account in the wider sense, as an investigation of localisation, then several cases of special localization tasks are known, which can be classified into two further groups of applications of track detectors. A survey of the applications of solid slate nuclear track detectors for all kinds of radiography is given on the basis of this definition of localisation experiments.     

Autoradiographische Abbildung von 14N-Verteilungen mit Festkörperspurdetektoren

Laterale Verteilungen von Stickstoff in Festkörpern können mit Hilfe der nentroneninduzierten Autoradiographie auf Grund der Reaktion ¹⁴N (n, p)¹¹C aufgenommen werden. Als Festkörperspurdetektor werden kommerzielle Zellulosenitratfolien vom Typ LR 115 und CA 80—15 und auch selbsthergestellte CN-Folien eingesetzt.⁺

Die Ätz- und Bestrahlungsbedingungen werden dargestellt. Aus experimentellen Untersuchungen biologischer Objekte und stickstoffhaltiger Festkörperproben etgab sich für Stickstoff eine untere Nachweisgrenze von ungefähr 1 Gew.-%.     

Application of 35S as a Radioactive Tracer for a Determination of the Composition and the Structure of Dispersion Coatings,Containing MoS2

A method is proposed for the determination of the content and distribution of MoS₂ in Ni-P-MoS₂, coatings deposited on a steel using ³⁵S as a radioactive tracer. ³⁵S is isolated and measured as BaSO₄. At the same time this approach gives the possibility to perform an autoradiographic investigation which enlarges the metallographic data.     

Using NAA to the Determination of Antimony in Trichlorosilane with Substoichiometric Extraction

Neutron activation analysis has been applied to the determination of trace of antimony based on the substoichiometric extraction of Sb(III) with BPHA (N-benzoyl-N-phenyl hydroxylamine). The antimony contens in trichlorosilane or high purity silicon can be determined by the proposed method down to ppb range. The effect of acid concentration, shaking time, the amount of carrier and the decontamination factors were studied.