Results 111 to 120 of about 15,556 (304)

Spatial Spectrum Analysis of Wave-Front Correction with a Segmented Mirror [PDF]

open access: yes, 2003
An expression is derived for the spatial power spectrum of wave-front errors after correction with a segmented mirror. This includes estimates of the spectral contributions of segment piston and tilt corrections and spatial aliasing by a regular array of
Padin, Stephen
core  

Rapid Fabrication of Self‐Propelled and Steerable Magnetic Microcatheters for Precision Medicine

open access: yesAdvanced Materials, EarlyView.
A rapid Joule heating fabrication method for the production of self‐propelling, adaptive microcatheters, with tunable stiffness and integrated microfluidic channels is presented. Demonstrated through three microrobotic designs, including a steerable guiding catheter, an untethered wave‐crawling TubeBot, and a distal‐end propelled microcatheter, it was ...
Zhi Chen   +5 more
wiley   +1 more source

Image sharpening metrics and search strategies for indirect adaptive optics [PDF]

open access: yes, 2000
Adaptive optics is concerned with the correction of turbulence induced aberrations and mis-alignments in optical systems. It is an expensive and complicated technology which has been developed for astronomy and defence applications.
Doble, N., Doble, Nathan
core  

Smart co-phasing system for segmented mirror telescopes [PDF]

open access: yes, 2016
One of the main challenges in space observations is to observe always fainter and more compact objects. This can be achieved by increasing the telescope diameters.
Simar, Juan Felipe   +5 more
core   +1 more source

Active cophasing and aligning testbed with segmented mirrors

open access: yesOptics Express, 2011
An active segmented cophasing imaging testbed with a high accurate optical adjustment and control in nanoscale is set up. A two-dimensional dispersed fringe analysis method is used to calculate the piston error between the adjacent segments. Segments alignment of tip-tilt is fulfilled by overlapping diffraction pattern centroids of the individual ...
Weirui, Zhao, Genrui, Cao
openaire   +2 more sources

Water Permeates and Plasticizes Amorphous Carbon Dots: Unraveling the Inner Accessibility of the Nanoparticles by Glass Transition Studies

open access: yesAdvanced Materials, EarlyView.
The water permeability of amorphous carbon dots (CDs) is demonstrated by investigating their plasticization. Novel polyamide‐based and amorphous nanoparticles are synthesized by controlling their inner packing density. Water plasticization is evidenced by the decrease of the CDs glass transition temperature with increasing the hydration degree.
Elisa Sturabotti   +8 more
wiley   +1 more source

A segmented mirror antenna for radiometers [PDF]

open access: yes, 1989
An antenna is designed for the radiometer application of the planned NASA Earth Science Geostationary Platforms in the 1990's. The antenna consists of two parts: a regular parabolic dish of 5 meters in diameter which converts the radiation from feeds ...
Lee, S. W.   +3 more
core   +1 more source

Tough, Ductile, and Strong Hard‐Soft Cementitious Composite Enabled by Multi‐Material Additive Manufacturing

open access: yesAdvanced Materials, EarlyView.
Drawing inspiration from the layered hard‐soft architecture found in sea sponges, this work establishes a new framework for architected cementitious composites (ACC) through multi‐material additive manufacturing (MMAM) process. The integration of mortar and elastomer phases into layered architectures enables synergistic toughening mechanisms, including
Aimane Najmeddine   +5 more
wiley   +1 more source

Integrated Wavefront Detection for Large-Aperture Segmented Planar Mirrors: Concept & Principle

open access: yesPhotonics
Planar mirrors play a crucial role in autocollimation testing and optical beam relay systems of telescopes and other fields. However, for the next-generation large-aperture telescopes, typical monolithic planar mirrors fall short in meeting anticipated ...
Rui Sun, Qichang An, Xiaoxia Wu
doaj   +1 more source

Lattice‐Matched 2D Template Enables Efficient Cesium Tin Halide Perovskite Solar Cells

open access: yesAdvanced Materials, EarlyView.
Lattice‐matched 2D perovskite PEA2CsSn2I7 templates the out‐of‐plane growth of inorganic 3D γ‐CsSnI3 along the (110) plane, forming highly oriented 2D/3D tin halide perovskite heterostructures. With reduced trap states and mitigated δ‐phase impurities, the CsSnI3‐based solar cells achieve a power conversion efficiency of 15.27% and maintain stable ...
Hongzhe Anna Xu   +15 more
wiley   +1 more source

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