Nonlinear junction locator with the possibility of identifying nonlinear objects

It is concept of nonlinear radar with the ability to identify nonlinear object using DSB-signal in the role of the probe. The block diagram developed nonlinear junction radar. Here formalized tasks that are necessary for the efficient operation of the nonlinear radar, which helps to raise the accuracy of the identification of objects that include elements with nonlinear current-voltage characteristics

Use of ultra-wideband signals in nonlinear radar

The analysis is given of the ways to improve the sensitivity of nonlinear radar to eavesdropping devices having small dimensions and having in its composition nonlinear objects. We investigated the method to increase the sensitivity by using, as the probe signal ultra-wideband pulses together with the harmonic signal of microwave frequency, which could result in intermodulation effect, through which run the identification nonlinear objects among the plurality of reflectors, which do not apply to non-linear objects

Pulse modulation for ultra-wideband communication systems

The basic types of pulse modulation used for ultra-wideband communication systems are considered. The interactions between a modulated signal and additive white Gaussian noise are analyzed. The most noiseproof and optimum types of modulation for practical implementation are defined

Programming model of side-view synthetic aperture radar

The article considers the principle of operating a side-view Synthetic Aperture Radar on an unmanned aircraft, its mathematical model and software model algorithm, the results of the synthesis of radar images obtained by probing the Earth's surface relief area

Nonlinear junction locator with the possibility of identifying nonlinear objects

It is concept of nonlinear radar with the ability to identify nonlinear object using DSB-signal in the role of the probe. The block diagram developed nonlinear junction radar. Here formalized tasks that are necessary for the efficient operation of the nonlinear radar, which helps to raise the accuracy of the identification of objects that include elements with nonlinear current-voltage characteristics

Use of ultra-wideband signals in nonlinear radar

The analysis is given of the ways to improve the sensitivity of nonlinear radar to eavesdropping devices having small dimensions and having in its composition nonlinear objects. We investigated the method to increase the sensitivity by using, as the probe signal ultra-wideband pulses together with the harmonic signal of microwave frequency, which could result in intermodulation effect, through which run the identification nonlinear objects among the plurality of reflectors, which do not apply to non-linear objects

Benzothiadiazole derivatives functionalized with two different (hetero)aromatic donor groups: synthesis and evaluation as TiO2 sensitizers for DSSCs

A series of benzothiadiazole-based push-pull heterocyclic systems were synthesized and characterized in order to study the variations induced by different aromatic and heterocyclic donor groups in the optical, electronic and photovoltaic properties of DSSCs prepared with the respective cyanoacetic acid derivatives. The organic sensitizers bear a 5-hexyl-2,2’-bithienyl or N,N-diphenylanilino donor moieties conjugated with a thienyl-benzothiadiazole spacer functionalized with the electron acceptor/anchoring cyanoacetic acid group. The solar cell based on TiO2 sensitized with the novel dye bearing the 5-hexyl-2,2’-bithienyl donor, exhibited a power conversion efficiency of 0.95 % due the inefficient electron injection. Co-adsorption studies of the same dye resulted in enhanced photovoltaic conversion efficiency of 2.49 %, which represents an improvement of cell efficiency of 260 %. The sensitizer bearing the N,N-diphenylanilino donor exhibited 4.51 % power conversion efficiency, that was further enhanced by co-sensitization to 5.22 % efficiency.Thanks are due to Fundação para a Ciência e Tecnologia (FCT) for a PhD grant to S. S. M. Fernandes (SFRH/BD/87786/2012) and FEDERCOMPETE for financial support through the CQ/UM (Ref. UID/QUI/ 00686/2013 and UID/QUI/0686/2016). The NMR spectrometer Bruker Avance III 400 is part of the National NMR Network and was purchased within the framework of the National Program for Scientific Re-equipment, contract REDE/1517/RMN/2005 with funds from POCI 2010 (FEDER) and FCT. A. Pereira, D. Ivanou, and A. Mendes would like to acknowledge the European Commission through the Seventh Framework Programme, the Scientific Programme “Ideas” of the European Research Council for research and technological development as part of an Advanced Grant under grant agreement No 321315, which also partially funded this work.info:eu-repo/semantics/publishedVersio

Push-pull heterocyclic dyes based on pyrrole and thiophene: synthesis and evaluation of their optical, redox and photovoltaic properties

Three heterocyclic dyes were synthesized having in mind the changes in the photovoltaic, optical and redox properties by functionalization of 5-aryl-thieno[3,2-b]thiophene, 5-arylthiophene and bis-methylpyrrolylthiophene π-bridges with different donor, acceptor/anchoring groups. Knoevenagel condensation of the aldehyde precursors with 2-cyanoacetic acid was used to prepare the donor-acceptor functionalized heterocyclic molecules. These organic metal-free dyes are constituted by thieno[3,2-b]thiophene, arylthiophene, bis-methylpyrrolylthiophene, spacers and one or two cyanoacetic acid acceptor groups and different electron donor groups (alkoxyl, and pyrrole electron-rich heterocycle). The evaluation of the redox, optical and photovoltaic properties of these compounds indicate that 5-aryl-thieno[3,2-b]thiophene-based dye functionalized with an ethoxyl electron donor and a cyanoacetic acid electron acceptor group/anchoring moiety displays as sensitizer for DSSCs the best conversion efficiency (2.21%). It is mainly assigned to the higher molar extinction coefficient, long π-conjugation of the heterocyclic system, higher oxidation potential and strong electron donating capacity of the ethoxyl group compared to the pirrolyl moiety.Thanks are due to the Fundacao para a Ciencia e Tecnologia (FCT) for a PhD grant to S.S.M. Fernandes (SFRH/BD/87786/2012) and to FEDER-COMPETE for financial support at the research center CQUM (UID/QUI/0686/2016) and (UID/QUI/0686/2020). The NMR spectrometers are part of the National NMR Network (PTNMR) and are partially supported by Infrastructure Project No. 022161 (co-financed by FEDER through COMPETE 2020, POCI and PORL and FCT through PIDDAC). The group in Porto would like to acknowledge the European Commission through the Seventh Framework Programme, the Specific Programme "Ideas" of the European Research Council for research and technological development as part of an Advanced Grant under Grant No. 321315, which also partially funded this work. Some of this work was also performed under the project "SunStorage-Harvesting and storage of solar energy", with reference POCI-01-0145-FEDER-016387, funded by the European Regional Development Fund (ERDF), through COMPETE 2020-Operational Programme for Competitiveness and Internationalization (OPCI), and by national funds, through FCT. The group in Porto is also thankful to POCI-01-0145-FEDER-006939 (Laboratory for Process Engineering, Environment, Biotechnology and Energy-UID/EQU/00511/2013) funded by the European Regional Development Fund (ERDF), through COMPETE2020-Programa Operacional Competitividade e Internacionalizacao (POCI) and by national funds, LEPABE-2-ECO-INNOVATION, supported by the North Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERD). Institutional Review Board Statement: Not applicable