Reduced Graphene Oxide-Polycarbonate Electrodes on Different Supports for Symmetric Supercapacitors

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Tuning electrical and thermoelectric properties of freestanding graphene oxide papers by carbon nanotubes and heat treatment

Electrical conductivity and Seebeck coefficient of freestanding paper of graphene oxide (GO) and GO reduced by heat treatment at 180 degrees C (rGO) are tuned by addition of carbon nanotubes (CNT). The electrical conductivity of rGO with 50% of CNT is raised to similar to 2940 S/m from similar to 613 S/m for pure rGO or similar to 34 S/m for GO with 50% of CNT without reduction. Moreover, Seebeck coefficient of rGO increases with addition of CNT from -7.04 mu V/K for pure rGO to -20.82 mu V/K for rGO with 50% of CNT, presenting n-type conductivity. As result, calculated power factor PF is enhanced with increasing CNT concentration and the highest PF similar to 1.28 mu W/(K(2)m) is obtained for rGO with 50% of CNT.O.O. and G.G. also thank Portuguese Foundation for Science and Technology (FCT) for the GrantsNo. SFRH/BPD/77704/2011 and SFRH/BPD/84419/2012, respectively, as well as UID/EMS/00481/2013-FCT and CENTRO-01-0145-FEDER-022083. C.D. is thankful to FCT for grant SFRH/BD/101661/2014. E.M.F.V. is grateful for financial support through the FCT grant SFRH/BPD/95905/2013. A.T. acknowledges funds by FEDER through Programa Operacional Factores de Competitividade - COMPETE and national funds through FCT within CICECO Project No. - FCOMP-01-0124-FEDER-037271 (FCT Ref. PEst-C/CTM/LA0011/2013) and independent researcher grant No. IF/00602/2013. Seebeck coefficient measurements were supported by FCT with the reference project UID/EEA/04436/2013, by FEDER funds through the COMPETE 2020 - Programa Operacional Competitividade e Internacionalizacao (POCI) with the reference project POCI-01-0145-FEDER-006941 and by the project PTDC/CTM - NAN/5414/2014 (POCI-01-0145-FEDER-016723). M Ferro is acknowledged for STEM analysis

Application of instrumental and sensor means to study shape factor of the object (pyramid)

Вивчено вплив моделі піраміди Хеопса (матеріал – дерево, розмір основи 2,6 м, висота 1,7 м) на фізико-хімічні параметри зразків води. Показано, що всередині піраміди є зони підвищеної біологічної активності. Зроблено висновок, що вода, разом із методом кірліанографії, може бути використана як сенсор для вивчення топографії полів всередині піраміди.Influence of the Cheops pyramid model (material – tree, with 2,6 m foundation and 1,7 m height) on physicochemical parameters of water samples has been studied. It was shown that inside the pyramid there are zones of increased biological activity. It was concluded that water accompanied by kirlianography can be used as a sensor to study topography of fields inside the pyramid.Изучено влияние модели пирамиды Хеопса (материал – дерево, размер основания 2,6 м, высота 1,7 м) на физико-химические параметры образцов воды. Показано, что внутри пирамиды есть зоны повышенной биологической активности. Сделано заключение, что вода, совместно с методом кирлианографии, может быть использована как сенсор для изучения топографии полей внутри пирамиды

Drastic modification of graphene oxide properties by incorporation of nickel: a simple inorganic chemistry approach

Strong increase in electrical conductivity of graphene oxide (GO) (I a parts per thousand 10(-9) A) is found by addition of Ni nanoparticles (Ni-NPs) preliminarily solved by HCl (Ni-sol) (I a parts per thousand 10(-4) A) or powder (Ni-pow) obtained from this solution (I a parts per thousand 10(-6) A), while simply mixing GO with Ni-NPs an insulator similar to pure GO is obtained. Thus, Ni-sol and Ni-pow can be used to transform GO from insulator to semiconductor. One of the transformation mechanisms is Ni as spillover. At the same time, different kinds of the magnetic response are obtained on GO and reduced GO (rGO) samples with and without Ni. Weak paramagnetic response is detected in pure GO. Stronger paramagnetic behavior is observed for GO and rGO mixed with Ni-sol or Ni-pow. Pure rGO sample shows weak ferromagnetism represented by slim but visible hysteresis with remnant magnetization M (r) of 0.05 emu/g. GO with Ni-NPs presents clear hysteresis with M (r) of 2.8 emu/g, while sample prepared by addition of Ni-NPs to rGO presents the largest hysteresis with M (r) as high as 11.8 emu/g. Thus, the optimal procedure to obtain the magnetic response requested for particular application can be chosen