Photoconduction of Polar and Nonpolar Cuts of Undoped Sr0.61Ba0.39Nb2O6 Single Crystals

In the last two decades, variably doped strontium barium niobate (SBN) has attracted a lot of scientific interest mainly due to its specific non-linear optical response. Comparably, the parental compound, i.e., undoped SBN, appears to be less studied so far. Here, two different cuts of single-crystalline nominally pure strontium barium niobate in the composition Sr0.61Ba0.39Nb2O6 (SBN61) are comprehensively studied and analyzed with regard to their photoconductive responses. We present conductance measurements under systematically varied illumination conditions along either the polar z-axis or perpendicular to it (x-cut). Apart from a pronounced photoconductance (PC) already under daylight and a large effect upon super-bandgap illumination in general, we observe (i) distinct spectral features when sweeping the excitation wavelength over the sub-bandgap region as then discussed in the context of deep and shallow trap states, (ii) extremely slow long-term relaxation for both light-on and light-off transients in the range of hours and days, (iii) a critical dependence of the photoresponse on the pre-illumination history of the sample, and (iv) a current–voltage hysteresis depending on both the illumination and the electrical-measurement conditions in a complex manner.

Die Bedeutung des Elementes Barium in der Nuklearmedizin

ZusammenfassungVon Erdalkalimetallionen außer Beryllium ist bekannt, dass sie ein calcimimetisches Verhalten zeigen. Damit ist ihr Schicksal in vivo vorgezeichnet, das in einem beträchtlichen Maße durch den Einbau in Knochengewebe, welches zum Hauptteil aus Hydroxylapatit besteht, charakterisiert ist. In diesem Sinne wurde auch die Verwendung von Radionukliden dieser Elemente als Knochensucher forciert. Mit Ausnahme von Beryllium und Magnesium wurden Tierexperimente und Humananwendungen mit Radionukliden von Calcium, Strontium, Barium und Radium durchgeführt, wobei bis heute lediglich Strontium und Radium, in der Hauptsache als Therapienuklide zur palliativen Behandlung von Knochenmetastasen, Eingang in nuklearmedizinische Routineanwendungen gefunden haben. In diesem Übersichtsartikel werden die Radionuklide des Bariums vorgestellt, sowie deren Herstellung und Verwendung. Aktuelle Forschungsergebnisse mit Radionukliden des Bariums in Radiopharmazie und Nuklearmedizin werden präsentiert.

Eu2+-activated strontium-barium silicate: a positive solution for improving luminous efficacy and color uniformity of white light-emitting diodes

In this research we have studied the lighting enhancement method by analyzing chromatic performance and luminous flux of light emitting diodes that produce white light. In order to achieve expected results, it is necessary to mix Eu2+-activated strontium-barium silicate (SrBaSiO4:Eu2+) with its phosphor compounding, which has been demonstrated to have considerable influence on lighting performance. The results showed that with the gradually increasing concentration of yellow-green-emitting SrBaSiO4:Eu2+ phosphor in LEDs devices, at 8500 K, the color homogeneity and the lighting output received a great improvement. The color quality scale, on the other hand, responded negatively to the increase in SrBaSiO4:Eu2+. The impact of SrBaSiO4:Eu2+ on optical properties of WLEDs was confirmed. The final step to optimize SrBaSiO4:Eu2+ usage in lighting development is to figure out a suitable amount of particles and optimize their size.

INFLUENCE OF AGROCHEMICAL SOIL PROPERTIES ON YIELD AND CHEMICAL COMPOSITION OF RAUSHAN BARLEY GRAIN

The productivity of barley Raushan 24.9-53.1 tons per hectare on the farm (SKHPK) them. Michurin, Vavozhsky district of the Udmurt Republic for 2013-2019 had a positive average correlation (r = 0,46) with the pH of the arable layer, a positive weak correlation with the content in the arable layer of mobile phosphorus (r = 0,26), exchange potassium (r = 0.12) and humus (r = 0,12). The crop of 2017, had more potassium, sulfur, phosphorus, magnesium, silicon, calcium, sodium, manganese, tin, iron, rubidium, strontium, barium, zirconium, copper, zinc, titanium, selenium, nickel, vanadium, gadolinium, lithium, germanium, cobalt, tungsten, beryllium, cadmium, than their content in the grain of the 2018 crop. In 2018, the yield was lower by 14,2 centner per hectare of the 2017 crop, and barley kernels contained more bromine, aluminum, boron, molybdenum, thorium, chromium, cerium, lanthanum, niobium, tantalum, gallium