374 research outputs found

    Benzimidazolium Surfactants for Modification of Clays for Use with Styrenic Polymers

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    Nanocomposites of polystyrene (PS), acrylonitrile-butadiene-styrene copolymer (ABS) and high impact polystyrene (HIPS) were prepared with two new homologous benzimidazolium surfactants used as organic modifications for the clays. The morphology of the polymer/clay hybrids was evaluated by powder X-ray diffraction (XRD) and transmission electron microscopy (TEM), showing good overall dispersion of the clay. The thermal stability of the polymer/clay nanocomposites was enhanced, as evaluated by thermogravimetric analysis. From cone calorimetric measurements, the peak heat release rate of the nanocomposites was decreased by about the same amount as seen for other organically-modified, commercially available clays

    Spin precession and spin Hall effect in monolayer graphene/Pt nanostructures

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    Spin Hall effects have surged as promising phenomena for spin logics operations without ferromagnets. However, the magnitude of the detected electric signals at room temperature in metallic systems has been so far underwhelming. Here, we demonstrate a two-order of magnitude enhancement of the signal in monolayer graphene/Pt devices when compared to their fully metallic counterparts. The enhancement stems in part from efficient spin injection and the large resistivity of graphene but we also observe 100% spin absorption in Pt and find an unusually large effective spin Hall angle of up to 0.15. The large spin-to-charge conversion allows us to characterise spin precession in graphene under the presence of a magnetic field. Furthermore, by developing an analytical model based on the 1D diffusive spin-transport, we demonstrate that the effective spin-relaxation time in graphene can be accurately determined using the (inverse) spin Hall effect as a means of detection. This is a necessary step to gather full understanding of the consequences of spin absorption in spin Hall devices, which is known to suppress effective spin lifetimes in both metallic and graphene systems.Comment: 14 pages, 6 figures. Accepted in 2D Materials. https://doi.org/10.1088/2053-1583/aa882

    Microwave spectroscopy on magnetization reversal dynamics of nanomagnets with electronic detection

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    We demonstrate a detection method for microwave spectroscopy on magnetization reversal dynamics of nanomagnets. Measurement of the nanomagnet anisotropic magnetoresistance was used for probing how magnetization reversal is resonantly enhanced by microwave magnetic fields. We used Co strips of 2 um x 130 nm x 40 nm, and microwave fields were applied via an on-chip coplanar wave guide. The method was applied for demonstrating single domain-wall resonance, and studying the role of resonant domain-wall dynamics in magnetization reversal

    Toxoplasmic Infection in Pregnant Women from Cluj County and Neighbouring Area

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    Toxoplasmosis is an antropozoonosis very frequent in population as a benign usually asymptomatic disease. The problems are raised by the congenital form of this disease that may occur if the women acquire the parasite during pregnancy leading to congenital toxoplasmosis. In order to prevent congenital toxoplasmosis many countries have screening programs design to diagnose the acute infection during fertile age of female population. Our prospective serologic study over a selected group of 510 pregnant women in Cluj county area showed a 39 % prevalence of toxoplasmic infection among women of fertile age, with a predominance of acute toxoplasmic infection during first trimester of pregnancy (66.66%), representing the predominant cause of abortion in our study group. Annual infection risk for female population aged 20-33 years old is K = 0.67% in our geographic area. A 4 % of cases had IgM persistence for more than 1-year period, and another 7% demonstrate positive IgM along with positive IgG raising the possibility of persistency to 11% of cases. We find out that half of women address laboratory by their own initiative and we calculate that medium age of pregnant women with toxoplasmic immunity (positive IgG) was 28 years old

    Advanced breakup-nucleon enhancement of deuteron-induced reaction cross sections

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    Following the EUROfusion PPPT-programme action for an advanced modeling approach of deuteron-induced reaction cross sections, as well as specific data evaluations in addition of the TENDL files, an assessment of the details and corresponding outcome for the latter option of TALYS for the breakup model has been carried out. The breakup enhancement obtained in the meantime within computer code TALYS, by using the evaluated nucleon-induced reaction data of TENDL-2019, is particularly concerned. Discussion of the corresponding results, for deuteron-induced reactions on 58^{58}Ni, 96^{96}Zr, and 231^{231}Pa target nuclei up to 200 MeV incident energy, includes limitations still existing with reference to the direct-reaction account

    GENERAL ASPECTS REGARDING THE GROWTH FRESHWATER FISH IN CUBES, AN ALTERNATIVE FOR AQUACULTURE IN ROMANIA

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    Due to the increased consumption of fish, as an alternative to achieving healthy population nutrition, the development of European aquaculture also shows an increasing trend. At present, freshwater culture is about 42% of total European fish production. Valuable species, from an economic point of view, can be reared in intensive systems in cages on running waters or ponds, combined with less valuable species. There are also new species that are gradually becoming increasingly important for the fish industry in Europe. Freshwater aquaculture in Romania is based on rainbow trout and carp which are still predominant species, but there is significant demand for valuable fish species [11,12,16]. Â

    Fixed Point Arithmetic in SHE Scheme

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    The purpose of this paper is to investigate fixed-point arithmetic in ring-based Somewhat Homomorphic Encryption (SHE) schemes. We provide three main contributions: firstly, we investigate the representation of fixed-point numbers. We analyse the two representations from Dowlin et al, representing a fixed-point number as a large integer (encoded as a scaled polynomial) versus a polynomial-based fractional representation. We show that these two are, in fact, isomorphic by presenting an explicit isomorphism between the two that enables us to map the parameters from one representation to another. Secondly, given a computation and a bound on the fixed-point numbers used as inputs and scalars within the computation, we achieve a way of producing lower bounds on the plaintext modulus pp and the degree of the ring dd needed to support complex homomorphic operations. Finally, as an application of these bounds, we investigate homomorphic image processing

    Detection and Characterization of Solid Pancreatic Lesions (Contrast-Enhancement, Elastography, EUS-Guided Fine Needle Aspiration)

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    AbstractFor detection of small pancreatic tumors and characterization of focal pancreatic masses, endoscopic ultrasound (EUS) is the most sensitive of the imaging procedures currently available. Differential diagnosis between benign and malignant focal pancreatic masses based on the EUS appearance is difficult and frequently requires EUS-guided fine needle aspiration (EUS-FNA) for confirmation of malignancy. New techniques improve the sensitivity, specificity, and accuracy of the differential diagnosis, as well as diagnosis of small pancreatic tumors (less than 2 cm diameter) by using real-time elastography or contrast-enhanced EUS. Nevertheless, EUS-FNA is still required for the final diagnosis in most of the cases, which allows an evidence-based management with referral to either curative surgery or palliative chemoradiotherapy. This article is part of an expert video encyclopedia
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