Power supply for battery charging

В системах энергоснабжения космических аппаратов очень много внимания уделяется системам заряда аккумуляторных батарей. В состав данных систем входят фотоэлектрические преобразователи, преобразующие энергию солнца в электрический ток. Данные преобразователи имеют крайне низкие энергетические показатели. Предлагаемая работа направлена на повышение эффективности заряда аккумуляторных батарей, посредством применения резонансного инвертора.In the space power systems, much attention is paid to battery charging systems. The composition of these systems includes photoelectric converters that convert the energy of the sun into electric current. These converters have extremely low energy performance. The proposed paper is aimed at increasing the efficiency of batteries chargers, by applying a resonant inverter

Multi-Layer Inkjet Printed Contacts for Silicon Solar Cells: Preprint

Ag, Cu, and Ni metallizations were inkjet printed with near vacuum deposition quality. The approach developed can be easily extended to other conductors such as Pt, Pd, Au, etc. Thick highly conducting lines of Ag and Cu demonstrating good adhesion to glass, Si, and printed circuit board (PCB) have been printed at 100-200 C in air and N2 respectively. Ag grids were inkjet-printed on Si solar cells and fired through the silicon nitride AR layer at 850 C, resulting in 8% cells. Next generation inks, including an ink that etches silicon nitride, have now been developed. Multi-layer inkjet printing of the etching ink followed by Ag ink produced contacts under milder conditions and gave solar cells with efficiencies as high as 12%

Multi-Layer Inkjet Printed Contacts to Si

Ag, Cu, and Ni metallizations were inkjet printed with near vacuum deposition quality. The approach developed can be easily extended to other conductors such as Pt, Pd, Au, etc. Thick highly conducting lines of Ag and Cu demonstrating good adhesion to glass, Si, and printed circuit board (PCB) have been printed at 100-200 deg C in air and N2 respectively. Ag grids were inkjet-printed on Si solar cells and fired through the silicon nitride AR layer at 850 deg C, resulting in 8% cells. Next generation inks, including an ink that etches silicon nitride, have now been developed. Multi-layer inkjet printing of the etching ink followed by Ag ink produced contacts under milder conditions and gave solar cells with efficiencies as high as 12%

Conducting and Optical Properties of Transparent Conducting Indium-Doped Zinc Oxide Thin Films by Sol-Gel Processing

Transparent conducting oxides were successfully prepared from mixed zinc nitrate hexahydrate and indium nitrate hydrate solutions in ethylene glycol using sol-gel technique. The In content in the film was varied (0, 2, 10, 20, 40, 75 and 100 atom %). Films were prepared by spin coating of the liquid precursors followed by thermal decomposition at 400° C after each layer. According to X-ray diffraction (XRD) measurements, the pure ZnO and pure InO films (0 and at 100 % In) were crystalline as-deposited. The crystallinity was suppressed in mixed compositions such that the films with compositions between 10 and 75 at % were amorphous. All the films were transparent with the transmission cut-off frequency near 400 nm, which is characteristic of TCO materials. All as-deposited films were conductive with 0 and 100 atom % In having the lowest resistivities. The resistivity of all compositions were improved by post-deposition reducing anneal in pure Ar at 300° C. The lowest resistivity of 0.2 Ωcm was obtained for the pure ZnO after Ar anneal. It was two-orders of magnitude higher than reported in the literature for the In-doped ZnO, which was attributed to the low processing temperature. The resistivities of as-deposited and annealed in Ar films were increased by consequent air anneal at 300° C

Influence of Graphene Nanoplatelet Lateral Size on the Electrical Conductivity and Electromagnetic Interference Shielding Performance of Polyester Nanocomposites

Polyester nanocomposites reinforced with graphene nanoplatelets (GnPs) with two different lateral sizes are prepared by high shear mixing, followed by compression molding. The effects of the size and concentration of GnP, as well as of the processing method, on the electrical conductivity and electromagnetic interference (EMI) shielding behavior of these nanocomposites are experimentally investigated. The in-plane electrical conductivity of the nanocomposites with larger-size GnPs is approximately one order of magnitude higher than the cross-plane volume conductivity. According to the SEM images, the compression-induced alignments of GnPs is found to be responsible for this anisotropic behavior. The orientation of the small size GnPs in the composite is not influenced by the compression process as strongly, and consequently, the electrical conductivity of these nanocomposites exhibits only a slight anisotropy. The maximum EMI shielding effectiveness (SE) of 27 dB (reduction of 99.8% of the incident radiation) is achieved at 25 wt.% of the smaller-size GnP loading. Experimental results show that the EMI shielding mechanism of these composites has a strong dependency on the lateral dimension of GnPs. The non-aligned smaller-size GnPs are leveraged to obtain a relatively high absorption coefficient (≈40%). This absorption coefficient is superior to the existing single-filler bulk polymer composite with a similar thickness

Crossover between extrinsic and intrinsic dielectric loss mechanisms in SrTiO3 thin films at microwave frequencies

The do bias field. dependence of the dielectric loss in SrTi03 thin films deposited onto MgO substrate is investigated. The experimental data obtained at different frequencies of the ac field (8 and 16 GHz) from differently processed films (as deposited and oxygen annealed) strongly suggest the occurrence of a crossover in the dominant loss mechanism. The crossover is driven by the do bias field: at weak fields the loss is governed by an extrinsic mechanism(s) whereas, at higher fields, the contribution of an intrinsic mechanism (dc field-induced quasi-Debye loss) becomes predominant. (C) 2004 American Institute of Physics

Intrinsic and extrinsic loss contributions in SrTiO3 thin films at microwave frequencies

The behavior of dielectric loss in SrTiO3 thin films at different microwave frequencies under the dc bias voltage applied is analyzed. Two types of differently processed SrTiO3 thin films (as deposited and oxygen-annealed) deposited by the pulse laser deposition technique onto MgO single crystal substrate are investigated. The half-wave microstrip resonator with the resonance frequencies being 8 and 16 GHz at the first and second resonance modes respectively was used for the microwave characterization of the investigated thin films. The experimental data obtained strongly suggest the occurrence of a crossover between different dielectric loss contributions (extrinsic and intrinsic) in the films. The crossover is driven by the dc bias field: at weak fields the loss is governed by an extrinsic mechanism(s) whereas, at higher fields, the contribution of an intrinsic mechanism (dc field-induced quasi-Debye loss) becomes predominant. The results obtained allowed us to conclude that the quality of tunable ferroelectric films can be judged from the shape of the field dependence of the loss tangent