MINI-MACtm—A new generation dual—Band surveyor

1986 ◽  
Vol 60 (3) ◽  
pp. 221-228 ◽  
Author(s):  
Jonathan W. Ladd ◽  
Robert G. Welshe ◽  
Alison Brown ◽  
Mark Sturza
Keyword(s):  
2018 ◽  
Vol 10 (8) ◽  
pp. 978-983 ◽  
Author(s):  
T. Sedghi ◽  
T. Aribi ◽  
A. Kalami

AbstractA compact coplanar waveguide (CPW)-fed circular polarization (CP)-antenna for new generation applications with dual bands filtering performance along with CP feature based on unit-cell semi-fractal is proposed in this paper. The CP-antenna privileges from semi-fractal radiator causes to have a miniaturized size. The stopped bands are designed to suppress the interference with present WLAN and ITU-R satellite systems. These properties are obtained by embedding semi-fractal unit-cell patterns stubs at the radiator and applying two rectangular-shaped slits inside CPW ground plane and a pair of grounded L-shaped strips. By introducing the first step of semi-fractal strips, and the mirrored defected ground surface structures, dual-band rejection functionality at WLAN (5–6 GHz) and ITU-R (7.725–8.5 GHz) are practically obtained. Besides that, semi-fractal strips results to two orthogonal modes stimulation on the radiator and CP attribute are obtained at WiMAX (3.1–3.7 GHz). CP-antenna presents omni-directional radiation H-plane patterns over the applicational frequency band. The CP-antennas size is 25 mm × 25 mm and fabricated on commercially available FR4-epoxy substrate with 1 mm thickness. Measured results illustrate that the proposed ultimate CP-antenna with miniaturized structure, efficient impedance tuning characteristics, and adequate radiation performances is the best choice for new generation of wireless communications.


2021 ◽  
Author(s):  
Vicente Navarro ◽  
Javier Ventura-Traveset

With the current GNSS infrastructure development plans, over 120 GNSS satellites (including European Galileo satellites)will provide, already this decade, continuous data, in several frequencies, without interruption and on a permanent basis.This global and permanent GNSS infrastructure constitutes a major opportunity for GNSS science applications. In themeantime, recent advances in technology have contributed "de-facto" to the deployment of a large GNSS receiver arraybased on Internet of Things (IoT), affordable smart devices easy to find in everybody’s pockets. These devices – evolvingfast at each new generation – feature an increasing number of capabilities and sensors able to collect a variety ofmeasurements, improving GNSS performance. Among these capabilities, Galileo dual band smartphones receivers andAndroid’s support for raw GNSS data recording represent major steps forward for Positioning, Navigation and Timing (PNT)data processing improvements. Information gathering from these devices, commonly referred as crowdsourcing, opensthe door to new data-intensive analysis techniques in many science domains. At this point, collaboration between variousresearch groups is essential to harness the potential hidden behind the large volumes of data generated by thiscyberinfrastructure. Cloud Computing technologies extend traditional computational boundaries, enabling execution ofprocessing components close to the data. This paradigm shift offers seamless execution of interactive algorithms andanalytics, skipping lengthy downloads and setups. The resulting scenario, defined by a GNSS Big Data repository with colocatedprocessing capabilities, sets an excellent basis for the application of Artificial Intelligence / Machine Learning (ML)technologies in the context of GNSS. This unique opportunity for science has been recognized by the European SpaceAgency (ESA) with the creation of the Navigation Scientific Office, which leverages on GNSS infrastructure to deliverinnovative solutions across multiple scientific domains.


Author(s):  
Rustem Zairov ◽  
Alexey Dovzhenko ◽  
Kirill Sarkanich ◽  
Irek Nizameev ◽  
Andrey Luzhetskiy ◽  
...  

The report introduces hybrid polyelectrolyte-stabilized colloids combining blue and green emitting building blocks, that are citrate carbon dots (CDs) and [TbL]+ chelate complexes with 1,3-diketonate derivatives of calix[4]arene. The joint incorporation of green and blue emitting blocks into the polysodium polystyrenesulfonate (PSS) aggregates is carried out through the solvent-exchange synthetic technique. The coordinative binding between Tb3+ centers and CD surface groups in initial DMF solutions both facilitates joint incorporation of [TbL]+ complexes and the CDs into the PSS-based nanobeads and affects fluorescence properties of [TbL]+ complexes and CDs, as well as their ability to temperature sensing. The variation of the synthetic conditions is represented herein as a tool for tuning the fluorescent response of the blue and green emitting blocks upon heating and cooling. The revealed regularities enable developing either dual band luminescent colloids for monitoring temperature changes within 25-50 C through double color emission, or to transform the colloids into ratiometric temperature sensors via simple concentration variation of [TbL]+ and CDs in initial DMF solution. Novel hybrid carbon dots-terbium chelate PSS-based nanoplatform opens an avenue for new generation of sensitive and customizable single excited dual band nanothermometers.


Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3080
Author(s):  
Rustem R. Zairov ◽  
Alexey P. Dovzhenko ◽  
Kirill A. Sarkanich ◽  
Irek R. Nizameev ◽  
Andrey V. Luzhetskiy ◽  
...  

The report introduces hybrid polyelectrolyte-stabilized colloids combining blue and green-emitting building blocks, which are citrate carbon dots (CDs) and [TbL]+ chelate complexes with 1,3-diketonate derivatives of calix[4]arene. The joint incorporation of green and blue-emitting blocks into the polysodium polystyrenesulfonate (PSS) aggregates is carried out through the solvent-exchange synthetic technique. The coordinative binding between Tb3+ centers and CD surface groups in initial DMF solutions both facilitates joint incorporation of [TbL]+ complexes and the CDs into the PSS-based nanobeads and affects fluorescence properties of [TbL]+ complexes and CDs, as well as their ability for temperature sensing. The variation of the synthetic conditions is represented herein as a tool for tuning the fluorescent response of the blue and green-emitting blocks upon heating and cooling. The revealed regularities enable developing either dual-band luminescent colloids for monitoring temperature changes within 25–50 °C through double color emission or transforming the colloids into ratiometric temperature sensors via simple concentration variation of [TbL]+ and CDs in the initial DMF solution. Novel hybrid carbon dots-terbium chelate PSS-based nanoplatform opens an avenue for a new generation of sensitive and customizable single excited dual-band nanothermometers.


2013 ◽  
Vol 8 (S299) ◽  
pp. 78-79
Author(s):  
A. Zurlo ◽  
A. Vigan ◽  
C. Moutou ◽  
D. Mesa ◽  
R. Gratton ◽  
...  

AbstractNext year the second generation instrument SPHERE will begin science operations at the Very Large Telecope (ESO). This instrument will be dedicated to the search for exoplanets through the direct imaging techniques, with the new generation extreme adaptive optics. In this poster, we present the performances of one of the focal instruments, the Infra-Red Dual-beam Imaging and Spectroscopy (IRDIS). All the results have been obtained with tests in laboratory, simulating the observing conditions in Paranal. We tested several configurations using the sub-system Integral Field Spectrograph (IFS) in parallel and simulating long coronographic exposures on a star, calibrating instrumental ghosts, checking the performance of the adaptive optics system and reducing data with the consortium pipeline. The contrast one can reach with IRDIS is of the order of 10−6 at 0.5 arcsec separation from the central star.


Author(s):  
D. Cherns

The use of high resolution electron microscopy (HREM) to determine the atomic structure of grain boundaries and interfaces is a topic of great current interest. Grain boundary structure has been considered for many years as central to an understanding of the mechanical and transport properties of materials. Some more recent attention has focussed on the atomic structures of metalsemiconductor interfaces which are believed to control electrical properties of contacts. The atomic structures of interfaces in semiconductor or metal multilayers is an area of growing interest for understanding the unusual electrical or mechanical properties which these new materials possess. However, although the point-to-point resolutions of currently available HREMs, ∼2-3Å, appear sufficient to solve many of these problems, few atomic models of grain boundaries and interfaces have been derived. Moreover, with a new generation of 300-400kV instruments promising resolutions in the 1.6-2.0 Å range, and resolutions better than 1.5Å expected from specialist instruments, it is an appropriate time to consider the usefulness of HREM for interface studies.


Author(s):  
Jorge Perdigao

In 1955, Buonocore introduced the etching of enamel with phosphoric acid. Bonding to enamel was created by mechanical interlocking of resin tags with enamel prisms. Enamel is an inert tissue whose main component is hydroxyapatite (98% by weight). Conversely, dentin is a wet living tissue crossed by tubules containing cellular extensions of the dental pulp. Dentin consists of 18% of organic material, primarily collagen. Several generations of dentin bonding systems (DBS) have been studied in the last 20 years. The dentin bond strengths associated with these DBS have been constantly lower than the enamel bond strengths. Recently, a new generation of DBS has been described. They are applied in three steps: an acid agent on enamel and dentin (total etch technique), two mixed primers and a bonding agent based on a methacrylate resin. They are supposed to bond composite resin to wet dentin through dentin organic component, forming a peculiar blended structure that is part tooth and part resin: the hybrid layer.


Author(s):  
S. J. Krause ◽  
W.W. Adams ◽  
S. Kumar ◽  
T. Reilly ◽  
T. Suziki

Scanning electron microscopy (SEM) of polymers at routine operating voltages of 15 to 25 keV can lead to beam damage and sample image distortion due to charging. Imaging polymer samples with low accelerating voltages (0.1 to 2.0 keV), at or near the “crossover point”, can reduce beam damage, eliminate charging, and improve contrast of surface detail. However, at low voltage, beam brightness is reduced and image resolution is degraded due to chromatic aberration. A new generation of instruments has improved brightness at low voltages, but a typical SEM with a tungsten hairpin filament will have a resolution limit of about 100nm at 1keV. Recently, a new field emission gun (FEG) SEM, the Hitachi S900, was introduced with a reported resolution of 0.8nm at 30keV and 5nm at 1keV. In this research we are reporting the results of imaging coated and uncoated polymer samples at accelerating voltages between 1keV and 30keV in a tungsten hairpin SEM and in the Hitachi S900 FEG SEM.


Author(s):  
Barbara Trask ◽  
Susan Allen ◽  
Anne Bergmann ◽  
Mari Christensen ◽  
Anne Fertitta ◽  
...  

Using fluorescence in situ hybridization (FISH), the positions of DNA sequences can be discretely marked with a fluorescent spot. The efficiency of marking DNA sequences of the size cloned in cosmids is 90-95%, and the fluorescent spots produced after FISH are ≈0.3 μm in diameter. Sites of two sequences can be distinguished using two-color FISH. Different reporter molecules, such as biotin or digoxigenin, are incorporated into DNA sequence probes by nick translation. These reporter molecules are labeled after hybridization with different fluorochromes, e.g., FITC and Texas Red. The development of dual band pass filters (Chromatechnology) allows these fluorochromes to be photographed simultaneously without registration shift.


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