12 research outputs found
Tracking of Human Arm Based on MEMS Sensors
Abstract. This paper studied the method for motion tracking of arm using triaxial accelerometer, triaxial gyroscope and electronic compass. The motion model of arm is established. The hardware of tracking system of arm is designed. The track method of arm gesture based on multi-sensors data fusion is analyzed. The compensation algorithm for motion accelerations is researched. The experimental results demonstrate that the motion acceleration compensation algorithm is validity, which can improve the dynamic measure precision of arm gesture angle
Modulation of Metabolome and Bacterial Community in Whole Crop Corn Silage by Inoculating Homofermentative Lactobacillus plantarum and Heterofermentative Lactobacillus buchneri
The present study investigated the species level based microbial community and metabolome in corn silage inoculated with or without homofermentative Lactobacillus plantarum and heterofermentative Lactobacillus buchneri using the PacBio SMRT Sequencing and time-of-flight mass spectrometry (GC-TOF/MS). Chopped whole crop corn was treated with (1) deionized water (control), (2) Lactobacillus plantarum, or (3) Lactobacillus buchneri. The chopped whole crop corn was ensiled in vacuum-sealed polyethylene bags containing 300 g of fresh forge for 90 days, with three replicates for each treatment. The results showed that a total of 979 substances were detected, and 316 different metabolites were identified. Some metabolites with antimicrobial activity were detected in whole crop corn silage, such as catechol, 3-phenyllactic acid, 4-hydroxybenzoic acid, azelaic acid, 3,4-dihydroxybenzoic acid and 4-hydroxycinnamic acid. Catechol, pyrogallol and ferulic acid with antioxidant property, 4-hydroxybutyrate with nervine activity, and linoleic acid with cholesterol lowering effects, were detected in present study. In addition, a flavoring agent of myristic acid and a depression mitigation substance of phenylethylamine were also found in this study. Samples treated with inoculants presented more biofunctional metabolites of organic acids, amino acids and phenolic acids than untreated samples. The Lactobacillus species covered over 98% after ensiling, and were mainly comprised by the L. acetotolerans, L. silagei, L. parafarraginis, L. buchneri and L. odoratitofui. As compared to the control silage, inoculation of L. plantarum increased the relative abundances of L. acetotolerans, L. buchneri and L. parafarraginis, and a considerable decline in the proportion of L. silagei was observed; whereas an obvious decrease in L. acetotolerans and increases in L. odoratitofui and L. farciminis were observed in the L. buchneri inoculated silage. Therefore, inoculation of L. plantarum and L. buchneri regulated the microbial composition and metabolome of the corn silage with different behaviors. The present results indicated that profiling of silage microbiome and metabolome might improve our current understanding of the biological process underlying silage formation
Electromechanical Impedance Response of a Cracked Timoshenko Beam
Typically, the Electromechanical Impedance (EMI) technique does not use an analytical model for basic damage identification. However, an accurate model is necessary for getting more information about any damage. In this paper, an EMI model is presented for predicting the electromechanical impedance of a cracked beam structure quantitatively. A coupled system of a cracked Timoshenko beam with a pair of PZT patches bonded on the top and bottom surfaces has been considered, where the bonding layers are assumed as a Kelvin-Voigt material. The shear lag model is introduced to describe the load transfer between the PZT patches and the beam structure. The beam crack is simulated as a massless torsional spring; the dynamic equations of the coupled system are derived, which include the crack information and the inertial forces of both PZT patches and adhesive layers. According to the boundary conditions and continuity conditions, the analytical expression of the admittance of PZT patch is obtained. In the case study, the influences of crack and the inertial forces of PZT patches are analyzed. The results show that: (1) the inertial forces affects significantly in high frequency band; and (2) the use of appropriate frequency range can improve the accuracy of damage identification
Fluorinated Linear Copolyimide Physically Crosslinked with Novel Fluorinated Hyperbranched Polyimide Containing Large Space Volumes for Enhanced Mechanical Properties and UV-Shielding Application
Fluorinated hyperbranched polyimide (FHBPI), a spherical polymer with large space volumes, was developed to enhance fluorinated linear copolyimide (FPI) in terms of mechanical, UV-shielding, and hydrophobic properties via simple blend and thermal imidization methods. FPI possessed superior compatibility with FHBPI, and no obvious phase separation was found. The incorporation of FHBPI led to the formation of physical crosslinked network between FPI and FHBPI, which markedly improved the mechanical properties of the FPI, resulting in maximum enhancement of 83% in tensile strength from 71.7 Mpa of the pure FPI to 131.4 Mpa of the FPI/FHBPI composite film containing 15 wt % of FHBPI. The introduction of FHBPI also changed the surface properties of composites from hydrophilicity to hydrophobicity, which endowed them with outstanding dielectric stability. Meanwhile, the thin FPI/FHBPI composites kept the high transparency in the visible spectrum, simultaneously showing enhanced UV-shielding properties and lifetimes under intense UV ray. This was attributed to the newly formed charge transfer complex (CTC) between FHBPI and FPI. Moreover, the FPI/FHBPI composites possessed preeminent thermal properties. The properties, mentioned above, gave the composites enormous potential for use as UV-shielding coatings in an environment filled with high temperatures and strong ultraviolet rays
Surface Properties and Structural Transformation Behaviors of mPEG-Maleic Rosin Copolymer in Water
mPEG (monomethoxy poly(ethylene glycol))-maleic rosin copolymer was successfully prepared. The surface properties of the copolymer were investigated by surface tension and resonance scattering techniques. The critical micelle concentration (CMC) was obtained. The adsorption behaviors and the conformational changes of the surfactant molecules at the air-water interface were described. The adsorption amount of state 1 presented a sinusoid shape and that of state 2 presented a sigmoid with the growth of П. The free energy of adsorption is more negative than that of micellization, thus, the surfactant molecules adsorb on the surface firstly, and then form micelles after saturation adsorption. Accordingly, structural transformation and aggregation behaviors of various concentration mPEG-maleic rosin copolymers with changing temperature were explored in water. The mPEG-maleic rosin chains experienced transformation from unimers to aggregates, to contracted aggregates, to cohesive aggregates with increasing temperature when the concentration is lower than CMC. This process is almost reversible with decreasing temperature. Transformation from micelle to aggregate with increasing temperature happened when the concentration is higher than CMC. The phenomena were assessed by DLS (dynamic light scattering) and SEM (scanning electron microscopy) techniques
Cyclic Water Clusters in Tape-Like and Cage-Like Structures
Controlling the ratio of 2,2′-bpy to benzene-1,3,5-tricarboxylic acid produces two interesting complexes, namely [Co(2,2′-bpy)3] (SO4) 8.5H2O (1) and [Cu2(BTCA) (2,2′-bpy)4] (OH) (2,2′-bpy)0.5·14H2O (2) (H3BTCA = benzene-1,3,5-tricarboxylic acid, 2,2′-bpy = 2,2′-bipyridine). We report the structural evidence in the solid state of discrete lamellar water cluster conformations. These units are found to act as supramolecular glue in the aggregation of cobalt (II) or copper (II) complexes to give three dimensional cage-like networks through hydrogen-bonding. It is interesting that the structure of complex 1 contains a 3D negatively charged cage