Anomalous Hall Effect in Bismuth

We report the occurrence of ferromagnetic-like anomalous Hall effect (AHE) below $30$ mT in bismuth single and policrystals. The signatures of ferromagnetism in transport are not corroborated in magnetization measurements, thus suggesting the induction of non-intrinsic magnetism at surfaces and grain boundaries in bismuth. The suppression of the AHE with the increase of magnetic field and temperature coincides with previous reports of superconductivity in Bi, suggesting an interplay between the two phenomena.Comment: AAM, peer-reviewed. 4 figures, 5 page

Nanocarbons And Quantum Dots Formation In New Hybrid Materials

We present technique of obtaining complex hybrid structures combining the multi-walled carbon nanotubes or multi-layer graphene and luminescent hydrophobic semiconductor core/shell quantum dots CdSe/ZnS. As a result, a formation of quantum dot decorated carbon nanotubes and graphene films is evidenced by 2D microluminescence and micro-Raman mapping of quantum dots and nanocarbons, respectively, where a spatial correlation between the luminescence and Raman signals is found. © 2014 SPIE.912612-02-00938; RFBR; Russian Foundation for Basic Research; 12-02-01263; RFBR; Russian Foundation for Basic ResearchKalantar-Zadeh, K., (2008) Nanotechnology-Enabled Sensors, p. 490. , K. Kalantar-zadeh, B. Fry. New York.: Springer Science & Business Media(1955) Springer Handbook of Nanotechnology, , Ed. B. Bhusha.-New York.: Springer Science & Business Media, 2010, ISBN: 978-3-642-02524-2Cattanach, K., Kulkarni, R.D., Kozlov, M., Manohar, S.K., Flexible carbon nanotube sensors for nerve agent simulants (2006) Nanotechnology, 17, pp. 4123-4128Peng, S., O'Keeffe, J., Wei, C., Cho, K., Kong, J., Chen, R., Franklin, N., Dai, H., Carbon nanotube chemical and mechanical sensors (2001) Proceedings of the 3rd International Workshop on Structural Health Monitoring, pp. 1-8. , USA, September 17-19, 2001, Stanford University, StanfordSnow, E.S., Perkins, F.K., Houser, E.H., Badescu, S.C., Reinecke, T.L., (2005) Science, 307, pp. 1942-1945. , Chemical detection with a single-walled carbon nanotube capacitorStar, A., Joshi, V., Skarupo, S., Thomas, D., Gabriel, J.-C.P., Gas sensor array based on metal-decorated carbon nanotubes (2006) J. Phys. Chem. B, 110, pp. 21014-21020Xu, Z., Gao, H., Guoxin, H., Solution-based synthesis and characterization of a silver nanoparticle-graphene hybrid film Carbon, 49 (14), pp. 4731-4738Cao, A., Liu, Z., Chu, S., Wu, M., Ye, Z., Cai, Z., Chang, Y., Liu, Y., A facile one-step method to produce graphene-cds quantum dot nanocomposites as promising optoelectronic materials (2010) Adv. Mater, 22, pp. 103-106Yang, Y.-K., He, Ch.-E., He, W.-J., Yu, L.-J., Peng, R.-G., Xie, X.-L., Wang, X.-B., Mai, Y.-W., Reduction of silver nanoparticles onto graphene oxide nanosheets with N,Ndimethylformamide and SERS activities of GO/Ag composites (2011) J Nanopart. Res, 13, pp. 5571-5581Lightcap, V., Kamat, P.V., Fortification of cdse quantum dots with graphene oxide. Excited state interactions and light energy conversion (2012) J. Am. Chem. Soc, 134, pp. 7109-7116Ghosh, A., Rao, K.V., Voggu, R., George, S.J., Non-covalent functionalization, solubilization of graphene and single-walled carbon nanotubes with aromatic donor and acceptor molecules (2010) Chemical Physics Letters, 488, pp. 198-201Kim, Y.-T., Han, J.H., Hong, B.H., Kwon, Y.-U., Electrochemical synthesis of cdse quantum-dot arrays on a graphene basal plane using mesoporous silica thin-film templates (2010) Adv. Mater, 22, pp. 515-518Konstantatos, G., Badioli, M., Gaudreau, L., Osmond, J., Bernechea, M., Arquer De Garcia, F.P., Gatti, F., Koppens, L.F.H., Hybrid graphene-quantum dot phototransistors with ultrahigh gain (2012) Nature Nanotechnology, 7, pp. 363-368Wang, Y., Yao, H.-B., Wang, X.-H., Yu, Sh.-H., One-pot facile decoration of CdSe quantum dots on graphene nanosheets: Novel graphene-CdSe nanocomposites with tunable fluorescent properties (2011) J. Mater. Chem, 21, pp. 562-566Murray, C.B., Gaschler, W., Sun, S., Doyle, H., Betley, T.A., Kagan, C.R., Colloidal synthesis of nanocrystals and nanocrystal superlattices IBM J. Res. & Dev., 45 (1), pp. 47-56Ermakov, V.A., Alaferdov, A.V., Vaz, A.R., Baranov, A.V., Moshkalev, S.A., Nonlocal laser annealing to improve thermal contacts between multi-layer graphene and metals (2013) Nanotechnology, 24 (15), p. 15530110Bogdanov, K., Fedorov, A., Osipov, V., Enoki, T., Takai, K., Hayashi, T., Ermakov, V., Moshkalev A, S., Annealing-induced structural changes of carbon onions: High-resolution transmission electron microscopy and Raman studies Baranov Carbon, , 02/201

Flexible highly conductive films based on expanded graphite /polymer nanocomposites

Highly electrically and thermally conducting films of expanded graphite/polymer nanocomposites were fabricated using an approach based on solution mixing methods. The use of Hydroxyethylcellulose and benzylic alcohol based solutions provides efficient dispersion and better exfoliation of multilayer graphene (nanographite) flakes that are further aligned in extended 2D layers forming continuous conductive pathways during lamination (hot calendering) process. Very high electrical conductivity (190 S/cm) was obtained for fabricated layered films. In contrast, for films produced by a conventional mixing and deposition method with acrylic copolymer and the same nanographitic material, with flakes randomly distributed within the composite, much lower conductivities (2.4 S/cm) were obtained

Micromechanics of liquid-phase exfoliation of a layered 2D material: A hydrodynamic peeling model

We present a micromechanical analysis of flow-induced peeling of a layered 2D material suspended in a liquid, for the first time accounting for realistic hydrodynamic loads. In our model, fluid forces trigger a fracture of the inter-layer interface by lifting a flexible “flap” of nanomaterial from the surface of a suspended microparticle. We show that the so far ignored dependence of the hydrodynamic load on the wedge angle produces a transition in the curve relating the critical fluid shear rate for peeling to the non-dimensional adhesion energy. For intermediate values of the non-dimensional adhesion energy, the critical shear rate saturates, yielding critical shear rate values that are drastically smaller than those predicted by a constant load assumption. Our results highlight the importance of accounting for realistic hydrodynamic loads in fracture mechanics models of liquid-phase exfoliation.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Energy Technolog

ИССЛЕДОВАНИЯ ПО ИЗВЛЕЧЕНИЮ ЦЕРИЯ ИЗ РАСТВОРОВ КОНЦЕНТРАТОВ РЕДКОЗЕМЕЛЬНЫХ МЕТАЛЛОВ ЭЛЕКТРОХИМИЧЕСКИМ И ЭКСТРАКЦИОННЫМ МЕТОДАМИ

In order to extract cerium from rare-earth metals (REM) recovered from Russian raw materials, the following modern domestic equipment was selected: OXITRON-58L-O2 diaphragm electrolyzer manufactured by LLC «Delfin Aqua» with the purpose of Ce(III) to Ce(IV) oxidation; EC-10FA centrifugal extractor manufactured by LLC «LIT» with the purpose of Ce(IV) extraction from the sum of REM. These units were used in the studies performed to identify conditions that would lead to cerium oxidation to a 4-valent state with the electrochemical method as well as to recover and clean Ce(IV) from rare-earth metals with the solvent extraction method. The experiments were performed with standardized test solutions of cerium nitrate and process solutions obtained using loparite concentrate from the Solikamsk Magnesium Plant. The conditions were identified and equipment operation modes were designed in order to enable the chosen electrolyzer model to achieve a degree of cerium oxidation in REM process solutions over 99 % at power consumption below 0,8 kW/h per 1 kg of CeO2, and extract cerium from REM concentrate solution using the laboratory cascade of 20 centrifugal extractors with further production of 99,6 % pure CeO2.Осуществлен выбор современного отечественного оборудования для извлечения церия из концентратов редкоземельных металлов (РЗМ), выделенных из российского сырья: диафрагменный электролизер OКСИТРОН-58Л-О2, изготовленный ООО «Делфин Аква», для проведения процесса окисления Ce(III) до Ce(IV); экстрактор центробежного типа модели ЭЦ-10ФА производства ООО «ЛИТ» для извлечения Ce(IV) из суммы РЗМ. На данном оборудовании проведены исследования режимов окисления церия до 4-валентного состояния электрохимическим методом, а также извлечения и очистки Се(IV) от РЗМ методом жидкостной экстракции. Эксперименты выполнены на модельных растворах нитрата церия и технологических растворах, полученных из лопаритового концентрата Соликамского магниевого завода. Определены условия и разработаны режимы работы оборудования, позволяющие на выбранной модели электролизера достичь степени окисления церия в технологических растворах РЗМ более чем на 99 % при расходе электроэнергии не более 0,8 кВт/ч на 1 кг СеО2, а на лабораторном каскаде из 20 экстракторов центробежного типа выделить церий из раствора концентрата РЗМ и получить СеО2 чистотой 99,6 %

Graphite nanobelts characterization and application for blood pulse sensing

In this work, graphite nanobelts-based films as a promising material for applications in flexible blood pulse sensors with low power consumption are studied. A modified Langmuir Blodgett method used here for the sensor fabrication, is a reliable, simple and scalable technique allowing for controlled deposition of conducting films with desired electrical properties. The nanobelts, deposited over oxidized silicon or onto flexible polydimethylsiloxane substrates, were morphologically and electrically characterized. The response of the sensors to blood pulses measured on wrists and necks of two different persons (a male and a female) and the ways of the sensor response optimization are discussed

Nonlocal laser annealing to improve thermal contacts between multi-layer graphene and metals

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The accuracy of thermal conductivity measurements by the micro-Raman technique for suspended multi-layer graphene flakes has been shown to depend critically on the quality of the thermal contacts between the flakes and the metal electrodes used as the heat sink. The quality of the contacts can be improved by nonlocal laser annealing at increased power. The improvement of the thermal contacts to initially rough metal electrodes is attributed to local melting of the metal surface under laser heating, and increased area of real metal-graphene contact. Improvement of the thermal contacts between multi-layer graphene and a silicon oxide surface was also observed, with more efficient heat transfer from graphene as compared with the graphene-metal case.2415Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)INCT NAMITECMinistry of Education and Science of the Russian Federation [11.519.11.3020, 11.519.11.3026]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Ministry of Education and Science of the Russian Federation [11.519.11.3020, 11.519.11.3026