Results 71 to 80 of about 19,229 (302)

Mixed‐Metal Promotion in a Manganese‐Molybdenum Oxynitride as Catalyst to Integrate C─C and C─N Coupling Reactions for the Direct Synthesis of Acetonitrile from Syngas and Ammonia

open access: yesAdvanced Materials, EarlyView.
Transition metal oxy/carbo‐nitrides show great promise as catalysts for sustainable processes. A Mn‐Mo mixed‐metal oxynitride attains remarkable performance for the direct synthesis of acetonitrile, an important commodity chemical, via sequential C─N and C─C coupling from syngas (C1) and ammonia (N1) feedstocks.
M. Elena Martínez‐Monje   +7 more
wiley   +1 more source

Planar microstrip YAGI antenna array [PDF]

open access: yes, 1993
A directional microstrip antenna includes a driven patch surrounded by an isolated reflector and one or more coplanar directors, all separated from a ground plane on the order of 0.1 wavelength or less to provide end fire beam directivity without ...
Huang, John
core   +1 more source

Physical Intelligence in Small‐Scale Robots and Machines

open access: yesAdvanced Materials, EarlyView.
“Physical intelligence” (PI) empowers biological organisms and artificial machines, especially at the small scales, to perceive, adapt, and even reshape their complex, dynamic, and unstructured operation environments. This review summarizes recent milestones and future directions of PI in small‐scale robots and machines.
Huyue Chen, Metin Sitti
wiley   +1 more source

A Functional 2D Carbon Allotrope Combining Nanoporous Graphene and Biphenylene Segments

open access: yesAdvanced Materials, EarlyView.
The synthesis of a novel nanoporous graphene (NPG) is reported with biphenylene segments via thermal fusion of 12‐armchair porous graphene nanoribbons grown on gold surfaces. Characterization using STM, AFM, and DFT reveals low‐defect semiconducting behaviour and tunable band gaps.
Paula Angulo‐Portugal   +14 more
wiley   +1 more source

Sensitivity of Antenna Arrays for Long-Wavelength Radio Astronomy

open access: yes, 2010
A number of new and planned radio telescopes will consist of large arrays of low-gain antennas operating at frequencies below 300 MHz. In this frequency regime, Galactic noise can be a significant or dominant contribution to the total noise.
S. W. Ellingson, Senior Member
core   +2 more sources

Mutual Coupling Reduction Between Two PIFA Using Uni-Planar Fractal Based EBG for MIMO Application [PDF]

open access: yes, 2016
Fractal Structures based on Electromagnetic bandgap (EBG) can contribute to the mutual coupling reduction between microstrip antennas due to its capability of suppressing surface waves propagation in a given frequency range.
Al-Raweshidy, H   +3 more
core   +1 more source

Giant Berry‐phase‐Driven X‐Ray Beam Translations in Strain‐Engineered Semiconductor Crystals

open access: yesAdvanced Materials, EarlyView.
Due to the Berry‐phase effect, X‐rays propagating in deformed crystals undergo large translations, interesting for X‐ray optics applications. Here, the lattice expansion observed upon H irradiation of dilute‐nitride semiconductors is exploited to engineer the deformation landscape of selectively hydrogenated GaAsN epilayers.
Marco Felici   +9 more
wiley   +1 more source

Metamaterial Antennas Enhance MRI of the Eye and Occipital Brain

open access: yesAdvanced Materials, EarlyView.
A radiofrequency antenna platform comprising planar and bend configurations is developed, incorporating structurally integrated epsilon‐negative metamaterial unit cells to enhance MRI. These antennas enable high‐resolution in vivo human MRI of the eye, orbit, and occipital brain. Comprehensive validation, including simulations, phantom experiments, SAR,
Nandita Saha   +14 more
wiley   +1 more source

Calculation of optimal values of weight coefficients for compensation of the mutual coupling of antenna array elements

open access: yesФизика волновых процессов и радиотехнические системы
Background. Antenna arrays are widely used in a variety of modern radio engineering systems for wireless communication and radar. The phenomenon of mutual coupling of antenna elements, which is manifested in practical implementation, may cause noticeable
Anatoly M. Bobreshov   +4 more
doaj   +1 more source

Home - About - Disclaimer - Privacy