This study presents a novel method for determining the liquid level from the outside of a sealed container, which is based on the balance of echo energy received by two receiving sensors. The proposed method uses one transmitting transducer and two receiving sensors that are encapsulated in a coupling plane and arranged by certain rules. The calculation and comparison of echo energy are grounded on the difference ultrasonic impedance between gas and liquid media. First, by analyzing the propagation and attenuation characteristics of ultrasonic waves in a solid, an acoustic model for calculating the echo energy is established and simulated in MATLAB. Second, the proposed method is evaluated through a series of experiments. The difference and ratio of echo energy received by two receiving sensors are calculated and compared under two different coupling conditions. Two kinds of the sensors that are arranged by different rules are selected for measuring the liquid level, and the measurement are analyzed and discussed in detail. Finally, the experimental results indicate that the proposed method can meet the proposed accuracy requirements and can effectively solve the problems caused by some poor coupling conditions. Full article

The proposed method for measuring the liquid level focuses on the ultrasonic impedance and echo energy inside a metal wall, to which the sensor is attached directly, not on ultrasonic waves that penetrate the gas–liquid medium of a container. Firstly, by analyzing the sound field distribution characteristics of the sensor in a metal wall, this paper proposes the concept of an "energy circle" and discusses how to calculate echo energy under three different states in detail. Meanwhile, an ultrasonic transmitting and receiving circuit is designed to convert the echo energy inside the energy circle into its equivalent electric power. Secondly, in order to find the two critical states of the energy circle in the process of liquid level detection, a program is designed to help with calculating two critical positions automatically. Finally, the proposed method is evaluated through a series of experiments, and the experimental results indicate that the proposed method is effective and accurate in calibration of the liquid level outside a sealed metal container. Full article

Epimedium sagittatum (Sieb. et Zucc) Maxim is a member of the Berberidaceae family of basal eudicot plants, widely distributed and used as a traditional medicinal plant in China for therapeutic effects on many diseases with a long history. Recent data shows that E. sagittatum has a relatively large genome, with a haploid genome size of ~4496 Mbp, divided into a small number of only 12 diploid chromosomes (2n = 2x = 12). However, little is known about Epimedium genome structure and composition. Here we present the analysis of 691 kb of high-quality genomic sequence derived from 672 randomly selected plasmid clones of E. sagittatum genomic DNA, representing ~0.0154% of the genome. The sampled sequences comprised at least 78.41% repetitive DNA elements and 2.51% confirmed annotated gene sequences, with a total GC% content of 39%. Retrotransposons represented the major class of transposable element (TE) repeats identified (65.37% of all TE repeats), particularly LTR (Long Terminal Repeat) retrotransposons (52.27% of all TE repeats). Chromosome analysis and Fluorescence in situ Hybridization of Gypsy-Ty3 retrotransposons were performed to survey the E. sagittatum genome at the cytological level. Our data provide the first insights into the composition and structure of the E. sagittatum genome, and will facilitate the functional genomic analysis of this valuable medicinal plant. Full article