Design and Simulation of an Antenna-Coupled Microbolometer at 30 THz

Weproposeamodelofantenna-coupledmicrobolometertobeincludedinanarrayforreceivinganddetectinglongwaveinfrared (LWIR) electromagnetic radiation. The antenna is joined to microstrip bandpass filters thus forming a single metal structure to definetheoperationfrequencyband.Theantennaandmicrostripfiltersaremodeledinaluminumthinfilm.Themicrobolometer ismodeledwithsuperconductingniobium,alltogetheronasiliconnitridemembrane.Thesquaredpixelstructureisdesignedon asupportframeof2

Growth of vertically aligned ZnO nanorods using textured ZnO films

A hydrothermal method to grow vertical-aligned ZnO nanorod arrays on ZnO films obtained by atomic layer deposition (ALD) is presented. The growth of ZnO nanorods is studied as function of the crystallographic orientation of the ZnO films deposited on silicon (100) substrates. Different thicknesses of ZnO films around 40 to 180 nm were obtained and characterized before carrying out the growth process by hydrothermal methods. A textured ZnO layer with preferential direction in the normal c-axes is formed on substrates by the decomposition of diethylzinc to provide nucleation sites for vertical nanorod growth. Crystallographic orientation of the ZnO nanorods and ZnO-ALD films was determined by X-ray diffraction analysis. Composition, morphologies, length, size, and diameter of the nanorods were studied using a scanning electron microscope and energy dispersed x-ray spectroscopy analyses. In this work, it is demonstrated that crystallinity of the ZnO-ALD films plays an important role in the vertical-aligned ZnO nanorod growth. The nanorod arrays synthesized in solution had a diameter, length, density, and orientation desirable for a potential application as photosensitive materials in the manufacture of semiconductor-polymer solar cells

Pb(core)/ZnO(shell) nanowires obtained by microwave-assisted method

In this study, Pb-filled ZnO nanowires [Pb(core)/ZnO(shell)] were synthesized by a simple and novel one-step vapor transport and condensation method by microwave-assisted decomposition of zinc ferrite. The synthesis was performed using a conventional oven at 1000 W and 5 min of treatment. After synthesis, a spongy white cottonlike material was obtained in the condensation zone of the reaction system. HRTEM analysis revealed that product consists of a Pb-(core) with (fcc) cubic structure that preferentially grows in the [111] direction and a hexagonal wurtzite ZnO-(Shell) that grows in the [001] direction. Nanowire length was more than 5 μm and a statistical analysis determined that the shell and core diameters were 21.00 ± 3.00 and 4.00 ± 1.00 nm, respectively. Experimental, structural details, and synthesis mechanism are discussed in this stud

Quality and high yield synthesis of Ag nanowires by microwave-assisted hydrothermal method

Silver nanowires (Ag-NWs) were obtained using microwave-assisted hydrothermal method (MAH). The main advantage of the method is its high NWs production which is greater than 90%. It is also easy, fast, and highly reproducible process. One of the drawbacks presented so far in the synthesis of nanostructures by polyol path is the high temperature used in the process, which is superior than the boiling point of solvent (ethylene glycol), and also its excessive reaction time. Here, Ag-NWs with diameters of 70 to 110 nm were synthesized in 5 min in large quantities. Results showed that dimensions and shape of nanowires were very susceptible to changes with reaction parameters. The reactor power and reactor fill capacity were important for the synthesis. It was found that the reaction time needs to be decreased because of the NWs which start to deform and break up due to significant increase in the pressure's system. Energy-dispersive X-ray spectroscopy and electron diffraction analysis (SAED) did not show corresponding phases of AgO. Some aspects about synthesis parameters which are related to the percent yield and size of nanowires are also discussed

Synthesis of Fe nanoparticles functionalized with oleic acid synthesized by inert gas condensation

In this work, we study the synthesis of monodispersed Fe nanoparticles (Fe-NPs) in situ functionalized with oleic acid. The nanoparticles were self-assembled by inert gas condensation (IGC) technique by using magnetron-sputtering process. Structural characterization of Fe-NPs was performed by transmission electron microscopy (TEM). Particle size control was carried out through the following parameters: (i) condensation zone length, (ii) magnetron power, and (iii) gas flow (Ar and He). Typically the nanoparticles generated by IGC showed diameters which ranged from ∼0.7 to 20 nm. Mass spectroscopy of Fe-NPs in the deposition system allowed the study of in situ nanoparticle formation, through a quadrupole mass filter (QMF) that one can use together with a mass filter. When the deposition system works without quadrupole mass filter, the particle diameter distribution is around +/−20%. When the quadrupole is in line, then the distribution can be reduced to around +/−2%

Hybrid Materials Based on Nanoparticles Functionalized with Alkylsilanes Covalently Anchored to Epoxy Matrices

In this work, the surface modification of zinc oxide nanoparticles (ZnO-NPs) with 3-glycidyloxy-propyl-trimethoxysilane (GPTMS) was investigated. The ZnO-NPs were synthesized using the physical method of continuous arc discharge in controlled atmosphere (DARC-AC). The surface modification was carried out using a chemical method with constant agitation for 24 h at room temperature. This surface functionalization of zinc oxide nanoparticles (ZnO-NPs-GPTMS) was experimentally confirmed by infrared spectroscopy (FT-IR), TGA, and XRD, and its morphological characterization was performed with SEM. The increase in mechanical bending properties in the two final hybrid materials compared to the base polymers was verified. An average increase of 67% was achieved with a moderate decrease in ductility. In the case of compressive strength, they showed mixed results, maintaining the properties. With respect to thermal properties, it was observed that inorganic reinforcement conferred resistance to degradation on the base material, giving a greater resistance to high temperatures

Hybrid Materials Based on Nanoparticles Functionalized with Alkylsilanes Covalently Anchored to Epoxy Matrices

In this work, the surface modification of zinc oxide nanoparticles (ZnO-NPs) with 3-glycidyloxy-propyl-trimethoxysilane (GPTMS) was investigated. The ZnO-NPs were synthesized using the physical method of continuous arc discharge in controlled atmosphere (DARC-AC). The surface modification was carried out using a chemical method with constant agitation for 24 h at room temperature. This surface functionalization of zinc oxide nanoparticles (ZnO-NPs-GPTMS) was experimentally confirmed by infrared spectroscopy (FT-IR), TGA, and XRD, and its morphological characterization was performed with SEM. The increase in mechanical bending properties in the two final hybrid materials compared to the base polymers was verified. An average increase of 67% was achieved with a moderate decrease in ductility. In the case of compressive strength, they showed mixed results, maintaining the properties. With respect to thermal properties, it was observed that inorganic reinforcement conferred resistance to degradation on the base material, giving a greater resistance to high temperatures

Optical and structural characterization of oleic acid-stabilized CdTe nanocrystals for solution thin film processing

This work presents results of the optical and structural characterization of oleic acid-stabilized cadmium telluride nanocrystals (CdTe-NC) synthesized by an organometallic route. After being cleaned, the CdTe-NC were dispersed in toluene to obtain an ink-like dispersion, which was drop-cast on glass substrate to deposit a thin film. The CdTe-NC colloidal dispersion as well as the CdTe drop-cast thin films were characterized with regard to the optical and structural properties. TEM analysis indicates that the CdTe-NC have a nearly spherical shape (3.5 nm as mean size). Electron diffraction and XRD diffraction analyses indicated the bulk-CdTe face-centered cubic structure for CdTe-NC. An additional diffraction line corresponding to the octahedral Cd3P2 was also detected as a secondary phase, which probably originates by reacting free cadmium ions with trioctylphosphine (the tellurium reducing agent). The Raman spectrum exhibits two broad bands centered at 141.6 and 162.3 cm−1, which could be associated to the TO and LO modes of cubic CdTe nanocrystals, respectively. Additional peaks located in the 222 to 324 cm−1 range, agree fairly well with the wavenumbers reported for TO modes of octahedral Cd3P2

Allende vive 30 años

El Seminario Internacional 30 Años Allende Vive, convocado por la Revista América Libre, el Centro de Educación Popular, CEPIS, de Brasil, el Centro Martín Luther King de Cuba y el ICAL, en un momento en que las luchas populares retoman la iniciativa, se planteó rescatar la memoria del proceso de la Unidad Popular y del ejemplo de Salvador Allende y proyectarla a las búsquedas que los movimientos populares realizan para construir alternativas al neoliberalismo, la emergencia de nuevos gobiernos populares, los caminos de creación de poder popular, la perspectiva socialista como proyecto y como opción. La publicación del seminario 30 Años Allende Vive constituye un aporte para la reflexión de la izquierda latinoamericana, y una importante fuente de consulta tanto para referencias históricas como para los muy actuales debates sobre la construcción de alternativas de cambio con perspectiva socialista.Presentación; Discurso de Inauguración del Seminario Internacional 30 Años, Allende Vive; Inauguración del Seminario 30 Años, Allende Vive; Saludos; Transformaciones de Estructura y Redistribución del Ingreso; La educación y la cultura en el Gobierno Popular; Reforma Agraria y Soberanía Alimentaria; Los logros de la Unidad Popular y las perspectivas en diferentes sectores sociales; Soberanía sobre los Recursos Naturales. El Cobre; El programa de gobierno de Salvador Allende; La Verdad sobre la Unidad Popular y el Golpe de Estado; Unidad Popular, Impacto y Solidaridad Internacional; Presentación del libro Salvador Allende, Textos Escogidos; La política imperialista. El ALCA y la militarización del mundo. El Plan Colombia; La unidad de los pueblos contra la estrategia imperialista, guerrerista, desestabilizadora y golpista de Estados Unidos; Ponencia de las Fuerzas Armadas Revolucionarias de Colombia Ejército del Pueblo (FARC-EP); Los cristianos en la lucha por el socialismo; Fuerzas Armadas, Democracia y Soberanía Nacional; Situación del movimiento sindical antes y después del golpe; Derechos Humanos antes y después del golpe de estado; Movimientos GLBTT y Procesos Revolucionarios en América Latina. Construyendo el nuevo sujeto histórico; Políticas de Género de la Izquierda Latinoamericana; Panel sobre Medios de comunicación; Gobernar la revolución. Por una gobernabilidad revolucionaria para la revolución bolivariana; La integración latinoamericana y el sueño bolivariano; Las alternativas populares en América Latina ayer y hoy. Izquierda e Institucionalidad, Reforma y Revolución; Los movimientos sociales y los partidos políticos en la construcción de las alternativas populares. Sujeto histórico, alianzas, programas, estrategias; La perspectiva socialista en la construcción de las alternativas populare