Compensation of Frequency-Dependent Attenuation for Tissue Harmonic Pulse Compression Imaging

Tissue harmonic imaging (THI) is highly effective for correct diagnosis. On the other hand, pulse compression is often used in a radar system and an ultrasound imaging system to perform high SNR measurement. Therefore, the performance of pulse compression of tissue harmonic imaging is required to be improved. The frequency-dependent attenuation (FDA) is a crucial problem in medical tissue imaging. In the pulse compression imaging, the deterioration of echoes by the FDA lowers the performance of a matched filtering using an ideal transmitted pulse as a template signal. Since, especially in the harmonic imaging, higher-frequency components are used for imaging than the fundamental imaging, the compensation of the FDA is strongly important for high-definition imaging. In this study, we examine a method to reduce the influence of the FDA on harmonics

Spectrum-Free Estimation of Doppler Velocities Using Ultra-Wideband Radar

A method for estimating Doppler velocities using ultra-wideband radar data is presented. Unlike conventional time-frequency analysis, the proposed method can directly obtain Doppler velocities without searching for peaks in a spectrum. By exploiting closed-form solutions for the Doppler velocities, it avoids the trade-off between time and frequency resolution, thus maintaining high time resolution. Both simulations and measurements are used to evaluate the proposed method versus conventional techniques

A 24 GHz FM-CW Radar System for Detecting Closed Multiple Targets and Its Applications in Actual Scenes

This paper develops a 24 GHz band FM-CW radar system to detect closed multiple targets in a small displacement environment, and its performance is analyzed by computer simulation. The FM-CW radar system uses a differential detection method for removing any signals from background objects and uses a tunable FIR filtering in signal processing for detecting multiple targets. The differential detection method enables the correct detection of both the distance and small displacement at the same time for each target at the FM-CW radar according to the received signals. The basic performance of the FM-CW radar system is analyzed by computer simulation, and the distance and small displacement of a single target are measured in field experiments. The computer simulations are carried out for evaluating the proposed detection method with tunable FIR filtering for the FM-CW radar and for analyzing the performance according to the parameters in a closed multiple targets environment. The results of simulation show that our 24 GHz band FM-CW radar with the proposed detection method can effectively detect both the distance and the small displacement for each target in multiple moving targets environments. Moreover, we develop an IoT-based application for monitoring several targets at the same time in actual scenes

Mass spectrometry-based fragmentation as an identification tool in lignomics

The ensemble of all phenolics for which the biosynthesis is coregulated with lignin biosynthesis, i.e., metabolites from the general phenylpropanoid, monolignol, and (neo)-lignan biosynthetic pathways and their derivatives, as well as the lignin oligomers, is coined the lignome. In lignifying tissues, the lignome comprises a significant portion of the metabolome. However, as is true for metabolomics in general, the structural elucidation of unknowns represents the biggest challenge in characterizing the lignome. To minimize the necessity to purify unknowns for NMR analysis, it would be desirable to be able to extract structural information from liquid chromatography-mass spectrometry data directly. However, mass spectral libraries for metabolomics are scarce, and no libraries exist for the lignome. Therefore, elucidating the gas-phase fragmentation behavior of the major bonding types encountered in lignome-associated molecules would considerably advance the systematic characterization of the lignome. By comparative MS" analysis of a series of molecules belonging to the beta-aryl ether, benzodioxane, phenylcoumaran, and resinol groups, we succeeded in annotating typical fragmentations for each of these bonding structures as well as fragmentations that enabled the identification of the aromatic units involved in each bonding structure. Consequently, this work lays the foundation for a detailed characterization of the lignome in different plant species, mutants, and transgenics and for the MS-based sequencing of lignin oligomers and (neo)lignans