Domoic acid in phytoplankton net samples and shellfish from the Krka River estuary in the Central Adriatic Sea

This paper deals with the precise identification of species of Pseudo-nitzschia, focusing on those which are a potential source of domoic acid, from the Krka River estuary of the Central Adriatic Sea. Domoic acid was measured in phytoplankton net samples and shellfish collected in the winter and early spring of 2011 and 2012. Domoic acid was only detected in early March 2011, both in plankton net samples and shellfish extracts, during a Pseudo-nitzschia species bloom. The measured concentrations of particulate domoic acid (DA) in filtered concentrated seawater varied from 3.1˗6.2 ng DA ml-1. In shellfish sample DA concentration was 0.2 μg g-1. Species belonging to the Pseudo-nitzschia delicatissima complex were more common than those from the Pseudo-nitzschia seriata complex. Morphological analyses by electron microscopy revealed the presence of three potentially toxic species: P. calliantha, P. pseudodelicatissima and P. pungens, and one non-toxic species: P. subfraudulenta. However, P. calliantha and P. pseudodelicatissima dominated during the March 2011 bloom. This study presents the first evaluation of particulate domoic acid along the Eastern Adriatic Sea and the first record of the presence of P. calliantha, P. pseudodelicatissima, P. pungens and P. subfraudulenta in the Krka River estuary

Spin-splitting in p-type Ge devices

Compressively strained Ge quantum well devices have a spin-splitting in applied magnetic field that is entirely consistent with a Zeeman effect in the heavy hole valence band. The spin orientation is determined by the biaxial strain in the quantum well with the relaxed SiGe buffer layers and is quantized in the growth direction perpendicular to the conducting channel. The measured spin-splitting in the resistivity ρxx agrees with the predictions of the Zeeman Hamiltonian where the Shubnikov-deHaas effect exhibits a loss of even filling factor minima in the resistivity ρxx with hole depletion from a gate field, increasing disorder or increasing temperature. There is no measurable Rashba spin-orbit coupling irrespective of the structural inversion asymmetry of the confining potential in low p-doped or undoped Ge quantum wells from a density of 6 × 1010 cm−2 in depletion mode to 1.7 × 1011 cm−2 in enhancement

A method for controlling the color rendering index for led RGBW modules

В статье предложен метод управления яркостями компонентов светодиодных модулей RGBW с использованием широтно-импульсной модуляции. Метод позволяет регулировать значение индекса цветопередачи Ra при фиксированных значениях цветности и общей яркости. Это даёт возможность управлять визуально воспринимаемой насыщенностью зелёных и красных цветов отражающих объектов. Экспериментальная проверка метода показала линейность изменения Ra в зависимости от яркости белого светодиода.This article proposes a method for controlling the components brightness of the RGBW led module using pulse-width modulation. The method allows adjusting the value of color rendering index Ra with fixed values of chromaticity and overall brightness. It`s allows to control visually perceived saturation of the green and red colors of reflective objects. Experimental verification of the method showed linearity Ra changes depending on the brightness of the white led

Upgraded LED illuminator for colorimetric research

В статье описана экспериментальная осветительная установка с использованием стандартных светоизлучающих диодов. Управление яркостью светодиодных компонентов осуществляется при помощи автоматизированной системы, представляющей собой комплекс драйверов с широтно-импульсной модуляцией. Исследуемая экспериментальная осветительная установка предназначена для регулирования значения индекса цветопередачи при фиксированных цветности и общей яркости, что позволяет управлять визуально-воспринимаемой насыщенностью зелёных и красных цветов отражающих объектов.The article describes an experimental lighting system using standard light-emitting diodes. Brightness of light-emitting iodes components are managed using an automated system, which is a set of drivers with pulse width modulation. The researched experimental lighting system designed to regulate the value of the color rendering index at fixed chromaticity and brightness that makes possible to control visually perceived saturation of green and red colors reflecting objects

Conductive screen printing inks by gelation of graphene dispersions

This paper describes the gelation of highly concentrated graphene/polymer dispersions triggered by mild heating. The gel formation is only dependent on the concentration of graphene with 3.25 mg mL−1 as the minimum value for graphene network formation. The graphene gel is then utilized for the preparation of colloidally stable and highly concentrated (52 mg mL−1) graphene pastes that demonstrate excellent performance in screen printing down to lines of 40 μm in width. Printed patterns dried at 100 °C for only 5 min exhibit sheet resistances of 30 Ω −1 at 25 μm thickness, thus, removing the need for long-time high temperature annealing, doping, or other treatments. Such a low drying temperature, high printing definition, and compatibility with industrially relevant plastic and paper substrates brings high-volume roll-to-roll application in printed flexible electronics within reach