141 research outputs found
Characterization of two geometrical isomers of (1,3-propanediamine-N,N'-diacetato-N,N'-di-3-propionato)nickelate(II). X-ray structure of the binuclear complex trans(O5)-[Ni2(1,3pddadp)(H2O)4].4H2O and octahedral distortion of edta-type chelates
No full textTwo - way SMA actuators for space application: performances and reliability
No full textAbstractWe demonstrate for the first time highly reliable actuators based on two-way shape memory effect (TWSME). Under life test, our actuators endure 300.000 loading cycles without performance degradation (fade out or amnesia). Further, we developed manufacturing technology which enables programming of the actuator deformation in austenite and martensite phase within the tolerance of ±6%. Novel actuators were qualified at the breadboard model level as the first TWSME actuators for space applications at the European Space Agency. The actuators are based on 50 μm thick NiTi alloy foil, doped with Cu. These novel actuators for the spacecraft thermal management system can reduce the mass of vane louvers from the current 4–5 kg/m2 to less than 500 g/m2. Further, due to the application of special optical coatings, the new louvers demonstrate better heat rejection efficiency than the existing systems
Application of Ni electroplating techniques towards stress-free microelectromechanical system based sensors and actuators
No full textPlasmonic Nanomembranes For Detection And Sensing
No full textNanomembranes, freestanding quasi-2D structures with thickness of the order of tens of nm and smaller and a giant aspect ratio with lateral dimensions of the order of millimeters, even centimeters, represent an important building blocks in micro and nanosystems [1], corresponding to ubiquitous bilipid membranes in living cells [2]. In this contribution we present our results in theory, design and experimental fabrication of metallic and metal-dielectric nanomembranes with plasmonic properties, intended for the use in the field of sensing. We first consider different approaches to functionalization and nanostructuring of nanomembranes [3]. These include introduction of noble metal or transparent conductive oxides fillers directly into the nanomembrane, lamination (multilayering) and patterning by 2D arrays of subwavelength nanoholes. Within this context we describe our results on nanofabrication of 8 nm thick chromium-based composite nanomembranes. Biomimetic structures utilizing nanochannel-based pores are also considered. We further present our results related to the design of chemical and biological sensors based on nanomembranes with plasmonic metamaterial properties [4]. Such sensors function as refractometric devices utilizing evanescent near fields as optical concentrators and adsorption-desorption mechanism, which ensures their ultra-high sensitivity that reaches single molecule detection [5]. We present some results on chemical sensors utilizing nanomembranes exhibiting extraordinary optical transmission, as well as those based on doublefishnet structures. Finally we consider the enhancement of infrared detectors by nanomembranes [6] utilizing the designer plasmon mechanism [7].\ud
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REFERENCES\ud
1. Jiang, C., Markutsya, S., Pikus, Y., and Tsukruk, V. V., Nature Mater., 3, 721-728 (2004).\ud
2. Matović, J., and Jakšić, Z., "Bionic (Nano)Membranes" in Biomimetics – Materials, Structures and Processes. Examples, Ideas and Case Studies, edited by Gruber, P.; Bruckner, D.; Hellmich, C.; Schmiedmayer, H.-B.; Stachelberger, H.; Gebeshuber, I. C., Berlin: Springer, 2011, pp 9-24.\ud
3. Jakšić, Z., and Matovic, J., Materials, 3, 165-200, (2010).\ud
4. Jakšić, Z., Vuković, S. M., Buha, J., and Matovic, J., J. Nanophotonics, 5, 051818 (2011)\ud
5. Jakšić, Z., Micro and Nanophotonics for Semiconductor Infrared Detectors: Towards an Ultimate Uncooled Device, Cham: Springer, 2014.\ud
6. Zijlstra, P., Paulo, P. M. R., and Orrit, M., Nature Nanotech., 7, 379-382 (2012).\ud
7. Pendry, J. B., Martín-Moreno, L., and Garcia-Vidal, F. J., Science, 305 847-848 (2004)
Field effect transistor based on protons as charge carriers
No full textAbstractWe demonstrated a field effect transistor based on the modulation of the proton flow in confined water-containing nanochannels. The device resembles an MOSFET transistor with the difference that the charge carriers here are ions (i.e. protons) instead of electrons. The effective cross-section of the conductive channels in the transistor is defined by the intensity of the electrical double layer and by the potential applied to the transistor gate
Composition of essential oils from three classes of juniper fruit from Serbia
No full textJuniperus communis L. (Cupressaceae) is widely distributed in the forest region of Serbia. This refers especially to degraded and devastated forests and abandoned farmlands. In addition to ecological significance as a pioneer species in forest regeneration, it is also of high economic interest. Its fruit (Juniperi fructi) produces a valuable essential oil (Juniperi aetherolium). Samples of J. communis fruits were collected from different places in Serbia and the content of essential oil was determined. Mature fruits were analyzed, with the content of unripe fruits up to 5%. The content of essential oils ranged between 2.30 and 2.66%. © 2011 Academic Journals
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