Radiation damping strongly perturbs remote resonances in presence of homo-nuclear mixing sequences

In this work, it is experimentally shown that the weak oscillating magnetic field (known as the “radiation damping” field) caused by the inductive coupling between the transverse magnetization of nuclei and the radio frequency circuit perturbs remote resonances when homo-nuclear total correlation mixing sequences are applied. Numerical simulations are used to rationalize this effect.

Electro-mechanically controlled assembly of reconfigurable 3D mesostructures and electronic devices based on dielectric elastomer platforms

The manufacture of 3D mesostructures is receiving rapidly increasing attention, because of the fundamental significance and practical applications across wide-ranging areas. The recently developed approach of buckling-guided assembly allows deterministic formation of complex 3D mesostructures in a broad set of functional materials, with feature sizes spanning nanoscale to centimeter-scale. Previous studies mostly exploited mechanically controlled assembly platforms using elastomer substrates, which limits the capabilities to achieve on-demand local assembly, and to reshape assembled mesostructures into distinct 3D configurations. This work introduces a set of design concepts and assembly strategies to utilize dielectric elastomer actuators as powerful platforms for the electro-mechanically controlled 3D assembly. Capabilities of sequential, local loading with desired strain distributions allow access to precisely tailored 3D mesostructures that can be reshaped into distinct geometries, as demonstrated by experimental and theoretical studies of ∼30 examples. A reconfigurable inductive–capacitive radio-frequency circuit consisting of morphable 3D capacitors serves as an application example.

Design of Impedance Matching Networks for RF Applications

This technical paper presents a design and study of impedance matching for RF (radio frequency) circuit application of common-source amplifier topology. Input and output matching networks of the amplifier were designed and computed ensuring unconditional stability. Inductors and capacitors are key passive components that are crucial for impedance matching, and are specifically designed such that they would satisfy the gain requirements at a specific frequency of operation. Impedance matching is necessary in RF circuit design to provide maximum possible power transfer between the source or the generator and the load. Complex tradeoffs among technology specifications and design parameters exist and should be carefully handled when designing the impedance matching networks, to optimize the performance of the amplifier.Â