Abstract: Provided herein is a novel formulation of a quasi-permanent charge-bearing nanofiber, and a one-step fabrication method of the nanofiber thereof. The novel formulation allows flexibility in adjusting the type of charges and crystallinity of the nanofiber product as desired, and the one-step fabrication method allows easy and cost-effective production of these nanofibers without the use of external physical charging. The charge-bearing nanofibers of the present invention also show remarkable stability under different temperature and chemical conditions, and a significant charge retention over a time period of 12 months.

Abstract: The present invention provides a nanofiber membrane with dual-scale porosity, fabricated through a phase-separation electrospinning process. The membrane consists of interconnected inter-fiber and surface pores, enhancing air permeability, diffusion rates, and filtration performance. The method employs solvents with distinct evaporation rates to induce phase separation during electrospinning, resulting in a highly porous structure. The nanofiber membrane is applicable in air filtration, medical dressings, drug delivery systems, and diagnostic test strips, offering improved performance characteristics such as reduced pressure drop, enhanced diffusion, and increased sensitivity in diagnostics. The process enables scalable, cost-effective production with consistent fiber morphology.

Abstract: There is provided an apparatus and method for performing unique word detection and frequency offset estimation for a receiver for DPSK signals comprising in-phase I and quadrature Q components for a plurality of symbols k. The apparatus comprises: a differential detector for performing differential detection of a received signal over a given symbol span; a frequency corrector for performing an initial correction of I and Q using a previously estimated value of the frequency offset; accumulators for averaging I and Q for each symbol k over a given number K of symbols, where K is the number of symbols in the unique word to be detected; a frequency offset estimation block for calculating an estimate of the frequency offset from averaged I and averaged Q; and a unique word detection block for determining, from differentially detected I, differentially detected Q, averaged I and averaged Q, whether or not the unique word is present in a received signal.

Abstract: There is provided an apparatus and method for estimating frequency offset for a receiver for DPSK signals comprising in-phase I and quadrature Q components for a plurality of symbols k. The apparatus comprises a differential detector for performing differential detection of a received signal over a symbol span of n symbols, where n is an integer greater than 1, a frequency corrector for performing an initial correction of I and Q using a previously estimated value of the frequency offset, a rotation block for rotating the phase of each symbol towards zero; and a calculator for calculating an estimate of the frequency offset by comparing the phase of each symbol with zero, the calculator being arranged to input the estimate into the frequency corrector for improving the previously estimated value of the frequency offset.