2. Mitteilung: Tetraphenylarsoniumverbindungen und Pentaphenylarsen

Es wurde ein Trennverfahren ausgeabeitet, das es gestattet, die Aktivitätsausbeuten für Mono-, Di- und Triphenylarsenverbindungen, für Tetraphenylarsoniumverbindungen und für Pentaphenylarsen sowie für nicht organisch gebundenes Arsen in neutronenbestrahlten Tetraphenylarsoniumver erbindungen und in Pentaphenylarsen zu bestimmen. Als Trennmethoden werden Extraktion, Ionenaustauwsch und Al₂O₃-Chromatographic benutzt. Zur Reinigung und Ausbeutebestimmung von Di- und Triphenylarsenprodukten sowie von Tetraphenylarsonimverbindungen finden Kristallisations- bzw. Fällungsreaktionen Anwendung unter Ausnutzung des Prinzips der Isotopenverdünnungsanalyse.     

Interaction Products of 12·5 Deuterons with Molybdenum and their Isolation Possibilities from Worn-out Cyclotron Parts

Using chemical separations and radiometric measurements medium-half-life irradiation products of molybdenum with 12.5 MeV deuterons were determined (⁹⁰Nb, ⁹²Nb, ^95mNb, ⁹⁵Nb, ⁹⁶Nb, ⁹⁹Mo, ^95mTc, ⁹⁶Tc, ^99mTc) as well as thick target yields for some of them: ⁹²Nb (0.22 μCi/μAh), ⁹⁵Nb(0.05 μCi/μAh), ⁹⁹Mo (64 μCi/μAh), ^95mTc(0.76 μCi/μAh), ⁹⁶Tc((62.5 μCi/μAh). Moreover isolation possibiities of radioactive preparations from removed worn-cut molybdenum parts of the U-120 cycletron are discussed.     

Transferkoeffizienten im System Boden—Pflanze in verschiedenen Lokalitäten der Tschechoslovakei

Für die Ermittlung der Transferkoeffizienten im System Boden–Pflanze wurden in drei Stellen der Tschechoslovakei Boden- und Pflanzenproben entnommen. Die niedrigsten Transferkoeffizienten für Getreide und für mehrjährige Futterpflanzen wurden in der Ostslovakei festgestellt. Die Werte der Transferkoeffizienten waren durch den Bodentyp, den Gesamt-Sorptionskapazität und dem Grad der Sorptionssättigung beeinfluβt.

Soil and plant samples were sampled for the determination of soil to plant transfer coefficients in three various Czechoslovak sites. The lowesl transfer factors for cereals and fodder were determined in the site of Eastern Slovakia. Values of transfer factors depend on soil type, cation exchange capacity and base saturation of soils.     

Isotope Zusammensetzung Der Mineralwässer Der Mongolei

Abstract

The isotopic composition (D, ¹⁸O, ⁸⁷Sr, ³He) of thermal and mineral waters of Mongolia is discussed. The Sr-isotope ratio depends on the rock's contact. Near the Chubsugul-lake ³He-/⁴He-values are high. A certain similarity between the waters of Mongolia and those of East Siberia can be derived from the obtained data.     

Zerstörungsfreie risstiefenbestimmung in Betonbauwerken mittels Radiotracerverfahren

At the Leipzig Technical University a method was developed, which allows to determine nondestructive the crack depth in concrete up to 15 cm. Based on a radiotracer technique the access to only one side of the object is required. The labelling of artificial-made cracks was carried out by use of a transport medium (not miscible with water) on the base of methyl isobutyl ketone (MIBK) and In- 113m as radionuclide. For the calculation of crack depth, measure-geometrical parameters were used. The improvement of the reliability of building-diagnostical interpretation using radio-physical parameters is described. A first application is provided for concrete structures below chemical equipments built as a barrier against ecologically harmful substances (petrol tanks). The intersectional aspect of further qualifications of the technique is emphasized.     

Two stage electrostatic separator for the recycling of plastics from waste electrical and electronic equipment

The aim of study was to evaluate the effectiveness of a new facility for recycling of plastics from granular waste electrical and electronic equipment. The installation consists of two sections, the products of a first tribo-aero-electrostatic separator being subsequently treated in two free-fall electrostatic separators. The tests were performed on a mixture of polycarbonate (PC) and polyamide (PA). Analysis of the purity of the products obtained was performed using a program of image processing in MATLAB. Products of very high purity (roughly 95% for both PC and PA) were obtained at a recovery rate higher than 70%.     

Multielement Analytical Spectroscopy in Plant Ionomics Research

Abstract: The study of the ionome (ionomics) is defined as quantitative and simultaneous measurement of the element composition of living organisms and changes in this composition in response to physiological stimuli, development stage, and genetic modifications (Salt et al., Ann. Rev. Plant Biol., Vol. 59, 2008). The necessity of understanding the regulation processes of elements in the organisms demands determination of many elements in the organism, tissue, and cell (Baxter, Plant Biol., Vol. 12, 2009). A prospect for ionomics is environmental pollution where great variety of conditions and pollutants exist resulting in concentration and interelemental changes in the plant ionome. The capabilities of and problems with several multielement analytical techniques, including instrumental neutron activation analysis (INAA), X-ray fluorescence, inductively coupled plasma–atomic emission spectrometry (ICP-AES), inductively coupled plasma–mass spectrometry (ICP-MS), and atomic absorption spectrometry (AAS), which are adequate and most promising in ionomic and environmental studies of plants, are reviewed. References are confined mainly to the last 10–15 years. Information about concentrations, roles, binding forms, and pollution sources of the elements and comparison between methods with respect to limits of detection, determined elements, interferences, and economic considerations are tabulated. Some combinations of instrumental techniques supplementing each other are highly valued, namely, ICP-MS and ICP-AES and INAA and AAS or ICP-AES.     

Monitoring cooperative equilibria in a stochastic differential game

This paper deals with a class of equilibria which are based on the use of memory strategies in the context of continuous-time stochastic differential games. In order to get interpretable results, we will focus the study on a stochastic differential game model of the exploitation of one species of fish by two competing fisheries. We explore the possibility of defining a so-called cooperative equilibrium, which will implement a fishing agreement. In order to obtain that equilibrium, one defines a monitoring variable and an associated retaliation scheme. Depending on the value of the monitoring variable, which provides some evidence of a deviation from the agreement, the probability increases that the mode of a game will change from a cooperative to a punitive one. Both the monitoring variable and the parameters of this jump process are design elements of the cooperative equilibrium. A cooperative equilibrium designed in this way is a solution concept for a switching diffusion game. We solve that game using the sufficient conditions for a feedback equilibrium which are given by a set of coupled HJB equations. A numerical analysis, approximating the solution of the HJB equations through an associated Markov game, enables us to show that there exist cooperative equilibria which dominate the classical feedback Nash equilibrium of the original diffusion game model.This research was supported by FNRS-Switzerland, NSERC-Canada, FCAR-Quebec.     

A novel scheme to acquire enhanced up-conversion emissions of Ho3+ and Yb3+ co-doped Sc2O3

A detailed investigation about the effect of Sc₂O₃: 1 mol%Ho³⁺/5 mol%Yb³⁺ co-doped with Ce⁴⁺ ions prepared by sol-gel methods was performed systematically. Under the excitation of 980 nm laser diode, both green emission (553 nm, ⁵F₄/⁵S₂→⁵I₈) and red emission (672 nm, ⁵F₅→⁵I₈) were both observed in the emission spectra of the samples, which were found to be two-photon process and sensitized by Yb³⁺ ions. With the increasing of Ce⁴⁺ ions, the up-conversion green emission intensity are increased by 6.52, 8.69, 10.85, 13.92 and 16.66 fold, corresponding to the Ce⁴⁺ ions concentrations from 5 mol% to 13 mol%, respectively. The number of photons are necessary to populate the upper emitting state decreases to 2 and the infrared absorption coefficient is reduced, when the Ce⁴⁺ ions concentration increase to 13 mol%. Ce⁴⁺ ions play an important role in tailoring the local crystal field around Ho³⁺ ions, lowering the highest phonon cut-off energy of matrix and reducing the infrared absorption coefficient, thus hindering the non-radiative processes, which contribute to the increased emission intensity. The excellent enhancement makes it a promising multifunctional optical luminescence material.     

熵的一种通俗教法

熵如力、能量和动量一样是物理学中一个重要概念,若能用一种通俗易懂的方法设计熵的教学,对文科物理的教学有重要意义.为此本文提出了一种通俗的熵的教法,这一教法不需要学生学习热力学第二定律也可以建立熵的概念.具体教学设计如下:通过日常生活例子引入熵的概念(也就是玻尔兹曼熵),设计两个例子让学生会计算熵,通过具体问题的讨论让学生充分理解熵的意义,通过一个实例由玻尔兹曼熵引入克劳修斯熵公式,设计一个演示实验强化教学效果,将熵与环境保护联系起来融入人文情怀,最后还强调了熵计算的不同层次.教学设计完全采用基于问题学习(PBL)的教学模式.