Public understanding of science and the perception of nanotechnology: the roles of interest in science,methodological knowledge,epistemological beliefs,and beliefs about science

In this article, we report data from an online questionnaire study with 587 respondents, representative for the adult U.S. population in terms of age, gender, and level of education. The aim of this study was to assess how interest in science and knowledge as well as beliefs about science are associated with risk and benefit perceptions of nanotechnology. The findings suggest that the U.S. public is still rather unfamiliar with nanotechnology. Those who have some knowledge mainly have gotten it from TV and the Internet. The content of current media reports is perceived as fairly positive. Knowledge of scientific methods is unrelated to benefit and risk perceptions, at least when other predictors are controlled. In contrast, positive beliefs about science (e.g., its impact on economy or health) and more sophisticated epistemological beliefs about the nature of scientific knowledge are moderately linked to more positive perceptions of nanotechnology. The only exception is the perception of scientific uncertainty: This is associated with less positive evaluations. Finally, higher engagement with science is associated with higher risk perceptions. These findings show that laypersons who are engaged with science and who are aware of the inherent uncertainty of scientific evidence might perceive nanotechnology in a somewhat more differentiated way, contrary to how it is portrayed in the media today.     

Elastic and plastic deformation of NaCl and Ni3Al polycrystals during compression in a multi-anvil apparatus

Abstract

The compression behaviour in a multi-anvil apparatus of pure NaCl and of a foil of Ni₃Al embedded in a pressure medium of NaCl has been studied by energy-dispersive X-ray diffraction. At ambient temperature, the pressure and stresses, determined from line positions of NaCl, were constant throughout the sample chamber. Line positions and line widths of NaCl reflections were reversible on pressure release. A saturation of microstrains observed in NaCl at 2 GPa is thus attributed to brittle fracture setting in at uniaxial stresses of around 0.3 GPa. Ni₃Al polycrystals, in contrast, undergo extensive (ductile) plastic deformation above 4 GPa. The compression behaviour of both Ni₃Al and NaCl is identical to that previously determined in a diamond anvil cell. While a multi-anvil device thus has the advantage, compared with a diamond anvil cell, of constant pressure and stress throughout the sample chamber, microstrains in poly-crystalline samples arise in both devices. Samples in a multi-anvil apparatus thus need to be mixed with a pressure medium and to consist of essentially single crystals just as in a diamond anvil cell. Annealing experiments at high pressures confirm that the release of the uniaxial stress component in the pressure medium does not cause a release of microstrains in the embedded sample if the latter has been plastically deformed. Annealing for the purpose of attaining hydrostatic conditions in compression studies thus has to be carried out with care.     

Heterodyne interferometric polarization coherent anti‐Stokes Raman scattering (HIP‐CARS) spectroscopy

We demonstrate a new technique that combines polarization sensitivity of the coherent anti‐Stokes Raman scattering (CARS) response with heterodyne amplification for background‐free detection of CARS signals. In this heterodyne interferometric polarization CARS (HIP‐CARS), the major drawbacks of polarization and heterodyne CARS are rectified. Using a home‐built picosecond optical parametric oscillator, we are able to address vibrational stretches between 600 and 1650 cm⁻¹ and record continuous high‐resolution Raman equivalent HIP‐CARS spectra. Copyright © 2010 John Wiley & Sons, Ltd.     

The influence of the substrate on the optical constants of Al films

Attenuated total reflection (ATR) spectroscopy employing a prism and a dielectric spacer layer is used to determine the optical constants of vacuum deposited aluminium films. In the energy range of the 1.5 eV interband transition, a strong dependence of the optical constants on the material of the underlying layer is found. This dependence is attributed to structural effects in the Al film.     

Kontinuierliche Konzentrationsbestimmung von Elektrolyten mit Hilfe der Oscillometrie

Zusammenfassung Die Messung der Elektrolytkonzentration in fließenden Lösungen, auch bei solchen, die Niederschläge oder Suspensionen enthalten, wird auf Grund der Veränderung des Dielektrikums einer Zelle, welche von einem elektrischen Hochfrequenzstrom durchflossen wird, durchgeführt. Auf diesem Wege ist die quantitative Bestimmung der Konzentration der gelösten Substanz oder die der durchlaufenden Menge beträchtlich vereinfacht und automatisiert. Dabei werden subjektive und Manipulationsfehler weitgehend ausgeschlossen. Die untersuchte Probe erleidet keinerlei Veränderungen.

---

Summary The electrolyte concentration of flowing solutions and of suspensions or solutions containing precipitates can be measured by the variation of the dielectrics in a cell, which is coupled with a high-frequency circuit. By means of this method the quantitative determination of the concentration of solutions or the determination of the quantity of ions passed through the tube can be simplified. The method makes possible an automatization and it precludes the possibility of subjective and manipulation errors. During the measurement the sample remains unchanged.