?? ????? ??????? ??? ????????????? ?????? ??????? ???? ??????? ????????????? ??? ???????? ?? 1978 ??? ?? ????? ?????? ???? ??? ?? 1980. ??????, ??????????? ??? 2020, ??????? 17 ???? ??? ??? ??????? 25 ?????????. ?? 1995 ?? ????? ??????????? ??? ????????? ?????? ???? ??????? ??? ??????, ???? ????????????????? ??? ???????? ??? ?????? ??? ????????? ?????? 8 ??? ??????????? ??? ??? ???? ??? ?????????. ?? ???????? ??? ????? ?????? ??? ????? ????????? ?? ????? ??????? ???? ?? ?? ????? ????????? ??????????? [1] ??? ?? ?????? ??????????? ???? ???????? [2], ???????? ??? Univ. of Southern California (???).

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서울 소재 7개 종합병원 암환자들의 보완대체요법 이용양상

Facile synthesis and characterization of conducting polymer-metal oxide based core-shell PANI-Pr2O–NiO–Co3O4 nanocomposite: As electrode material for supercapacitor

Thermoelectric materials, which can convert heat into electricity and vice versa, have essential applications in power generation, thermocouples, sensors, and cooling. In the past decade, a lot of ...

Oxychalcogenides as Thermoelectric Materials: An Overview

Advances and Perspectives for the Application of Perovskite Oxides in Supercapacitors

Mg-substitution effect on microstructure, dielectric relaxation and conduction phenomenon of Fe based perovskite nanomaterials

Temperature dependent conductivity mechanisms observed in Pr2NiTiO6

Existence of nearest-neighbor and variable range hopping in Pr2ZnMnO6 oxygen-intercalated pseudocapacitor electrode

Zero dimensional graphene quantum dots (GQDs) exhibit interesting physical and chemical properties due to the edge effect and quantum confinement. As the number of carbon atoms in edge is more than on basal plane, GQDs are more reactive. Room temperature XRD pattern confirms the formation of the GQDs. UV-Visible spectra confirm that GQDs show optical absorption in the visible region. The emission peaks in the photoluminescence spectra are red shifted with the increase of excitation wavelength. Dynamic light scattering (DLS) analysis shows that the average size of the particles is found to be ∼65 nm. The frequency dependent electrical transport properties of the GQDs are investigated in a temperature range from 300 to 500 K. Most interestingly, for the first time, the insulator to semiconductor transition of GQD is observed near 400K. The transition mechanism of GQD is discussed with detailed dielectric analysis. The effects of intercalated water on temperature dependent conductivity are clearly discussed. The dielectric relaxation mechanism is explained in the framework of permittivity, conductivity and impedance formalisms. The frequency dependent ac conductivity spectra follows the Jonscher’s universal power law. Cole-Cole model is used to investigate the dielectric relaxation mechanism in the sample.

Insulator to semiconductor transition in graphene quantum dots

Layered oxychalcogenide BiCuSeO is a promising thermoelectric material due to its ultra-low thermal conductivity and moderate Seebeck coefficient. The doping of monovalent/divalent elements at the Bi site helps in reducing the electrical resistivity. In this report, Bi1−xZnxCuSeO (x = 0.0, 0.02, 0.04, 0.06, 0.08, and 0.1) was prepared by the solid state synthesis to elucidate the Zn doping effect at the Bi site. Zinc oxide was used as a precursor to dope Zn at the Bi site. The X-ray diffraction patterns were matched with BiCuSeO with no additional peak, which confirms the crystal structure and phase purity of the samples. X-ray photo electron spectroscopy of the Bi0.90Zn0.10CuSeO sample indicated a coexistence of Bi+3 and Bi+4 oxidation states. The electrical resistivity and Seebeck coefficient of the samples decreased with increase in the doping concentration because of increasing carrier concentration. The electrical resistivity of all the doped samples showed a transition from a metallic to semiconducting nature around 473 K. The Seebeck coefficient of the samples with x = 0.06, 0.08 and 0.1 showed a very weak temperature dependence above 523 K, which is a signature of small polaron hopping. The highest power factor of 0.35 mW/m K2 was obtained for x = 0.02 at 773 K. The impedance spectroscopy of the Bi0.90Zn0.10CuSeO sample confirmed the hopping conductivity and also the increase in the mobility of the charge carrier with temperature. The total thermal conductivity was dominated by the lattice thermal conductivity. The highest zT of 0.48 at 773 K has been obtained for x = 0.02, mainly due to the increment in the power factor.

Thermoelectric Properties of Zn Doped BiCuSeO

Investigation of doping effect on electrical conduction mechanism and Li+ ion insertion/extraction in ZnO-XV2O5 {X=5% and 10%} electrode for superior energy storage application

Moumin Rudra

Papers

Temperature dependent conductivity mechanisms observed in Pr2NiTiO6

Existence of nearest-neighbor and variable range hopping in Pr2ZnMnO6 oxygen-intercalated pseudocapacitor electrode

Insulator to semiconductor transition in graphene quantum dots

Thermoelectric Properties of Zn Doped BiCuSeO

Investigation of doping effect on electrical conduction mechanism and Li+ ion insertion/extraction in ZnO-XV2O5 {X=5% and 10%} electrode for superior energy storage application