Reactively sputtered TiO2 layers on SnO2:F substrates: A Raman and surface photovoltage study

DC reactively sputtered TiO₂ layers on SnO₂:F substrates were investigated by Raman and surface photovoltage spectroscopy. The stoichiometry and layer thicknesses were investigated by elastic recoil detection analysis. The deposition temperature, the O₂/(O₂ + Ar) ratio and the deposition time were varied systematically. With increasing temperature, the layers become crystalline with the rutile modification dominating. Rutile phase preferentially forms on vertical facets of SnO₂ crystallites. Anatase phase starts to form during prolonged deposition and at lower O₂/(O₂ + Ar) ratios. The energy of the exponential absorption tails below the band gap, a measure of the defect density of the films, is determined by the deposition temperature and not by other parameters if the deposition temperature is relatively high, irrespective of the content of crystalline phases or the value of the band gap. Charge separation takes place at length scales significantly shorter than the layer thicknesses (diffusion length less than 6 nm). TiO₂ films sputtered at 380 °C show rectifying behaviour with a carbon contact.     

Upgrading of Symbolic and Synthetic Knowledge Bases: Evidence from the Chinese Automotive and Construction Industries

This paper deals with the question of how upgrading of the symbolic and synthetic knowledge bases takes place and, by doing so, we contribute to the upgrading literature by linking upgrading with the concept of the differentiated knowledge bases. We discern a number of upgrading mechanisms, and based on empirical evidence from the construction industry and the automotive industry in China, we show that the main upgrading mechanisms for symbolic knowledge include “learning-by-interacting in project teams” and “monitoring”, while upgrading of synthetic knowledge takes place via “technology transfer” and “learning-by-doing and-using”. “Mobility” and “on-the-job training and learning in Transnational Corporations” are the main upgrading mechanisms contributing to the development of both knowledge bases.     

Acute and chronic toxicity effects of silver nanoparticles (NPs) on Drosophila melanogaster

The use of nanoscaled materials is rapidly increasing, however, their possible ecotoxicological effects are still not precisely known. This work constitutes the first complex study focused on in vivo evaluation of the acute and chronic toxic effects and toxic limits of silver nanoparticles (NPs) on the eukaryotic organism Drosophila melanogaster. For the purpose of this study, silver NPs were prepared in the form of solid dispersion using microencapsulation method, where mannitol was used as an encapsulation agent. This newly prepared solid dispersion with a high concentration of silver NPs was exploited to prepare the standard Drosophila culture medium at a silver concentration range from 10 mg·L(-1) to 100 mg·L(-1) of Ag in the case of the acute toxicity testing and at a concentration equal to 5 mg·L(-1) in the case of the chronic toxicity testing. The acute toxic effect of silver NPs on Drosophila melanogaster was observed for the silver concentration equal to 20 mg·L(-1). At this silver concentration, 50% of the tested flies were unable to leave the pupae, and they did not finish their developmental cycle. Chronic toxicity of silver NPs was assessed by a long-term exposure of overall eight filial generations of Drosophila melanogaster to silver NPs. The long-term exposure to silver NPs influenced the fertility of Drosophila during the first three filial generations, nevertheless the fecundity of flies in subsequent generations consequently increased up to the level of the flies from the control sample due to the adaptability of flies to the silver NPs exposure.     

Über die Beschleunigung und Verzögerung von elektrischen Ladungsträgern im Vakuum bei explizit vorgegebenen elektrischen und kinetischen Randwerten

Übersicht Die Theorie der Ionenraketen basiert darauf, daß die elektrische Feldstärke und die Geschwindigkeit am Beginn der Beschleunigungsstrecke vernachlässigbar sind. Will man Ionen-Durchström-Triebwerke oder Ionen-Vielfachbeschleuniger konzipieren, so kann die elektrische Feldstärke und die Geschwindigkeit am Beginn der Umwandlungstrecke wesentlich von Null abweichen. Es wird deshalb hier eine Theorie der Ionenbeschleunigung entwickelt, bei der die elektrischen und kinetischen Randwerte innerhalb der physikalischen Grenzen frei wählbar sind und explizit vorgegeben werden können. Mit der gleichen Zielsetzung wird die Ionenverzögerung behandelt, welche die Grundlage für die Konzipierung von Ionenstrahl-Generatoren ist. Mit dieser Arbeit wird also ein Beitrag zur Theorie der elektrokinetischen Energiewandlungsprozesse geleistet.

---

On the acceleration and deceleration of electric charge carriers in vacuum with explicitely given electrical and kinetic boundary values

Contents The theory of ion rocket engines is based upon the neglection of the electric field strength and the velocity at the beginning of the acceleration path. In the design of ion-flow accelerators or multi-stage ion accelerators the strength of the electric field and the velocity at the beginning of the transfer path may differ significantly from zero. A theory of the ion acceleration is therefore developed, where the electrical and kinetic boundary values can be chosen freely within the limits of physics and where these boundary values can be given explicitely. With the same intent the deceleration of ions is treated: the basic design of ion-jet power generators. This paper may therefore be a contribution to the theory of processes of electro-kinetic energy transfer.

     

A new approach to the synthesis of 4-bar function generatorsNeue methoden für die synthese viergliedriger funktionsgeneratoren

In the present work a new approach to the synthesis of 4-bar function generators has been presented. Using this graphical method quick and at the same time sufficiently accurate synthesis is possible in a large number of cases. The method is based on the principle of coordinating two positions and the corresponding velocities of the input and the output links. Thus four conditions are satisfied and better accuracy than that with three point synthesis may be expected. Positions of the proper accuracy points have been discussed and some guidance to the selection of the initial data has been presented in this paper. One problem has been solved as an example.