Modeling and simulation of the structural and electrical characteristics for a polarized piezoelectric sensor actuator

Abstract The present work aims to design a new polarized piezoelectric sensor actuator. This sensor actuator not only can achieve sensing and execution at the same time, but also has the advantages of small size and high integration. A mathematical model of stack displacement with input voltage and number of layers was established. The relationship between the charge generated by quartz crystal and external force was numerically analysed. The static and modal analysis of the structure were carried out to obtain the measured force range and the maximum working frequency. The transient simulation is used to verify the follow-up law of the actuator to the alternating signal. The Electric field interference analysis of the piezoelectric sensor actuator was performed to eliminate the interference from the electric field generated by the actuator. The results show that the measured force range of the actuator is up to 1 kN, with the maximum working frequency is 1000 Hz, and the actuator can follow the drive voltage signal well, with an almost negligible electric field interference in the sensor part. This paper provides a new method and theory for the study of self-sensing actuators.</jats:p

Characterizing the Adsorption of Poly(vinyl alcohol) on Colloidal Silica with Aggregation-Induced Emission Fluorophore

The adsorption of polymer on colloidal particle has significant influence on colloid structure and dynamics. Here we introduce a new method to monitor the adsorption in situ, based on the different emission behavior of aggregation-induced emission (AIE) luminogen in different micro environments. Poly­(vinyl alcohol) (PVA) and colloidal silica (CS) were used as a model system. It was found that AIE molecules exhibited extremely low fluorescence intensity in water and PVA solution, while their emission efficiency was enhanced when adsorbed on CS, and became significantly boosted when PVA was adsorbed on CS at the same time. The fluorescence intensity increases with the amount of added PVA and reaches a saturation point, which is earlier than that obtained by the well-established solvent relaxation NMR method, due to their different sensitivities for adsorption segments in specific conformation. This new method is advantageous in quick response, where the measurement can be finished within 2 min, while others usually take hours. Therefore, it is expected that this new method may be used to monitor the dynamical adsorption process of polymer on colloidal particles

A fluorescent turn-on low dose detection of gamma-radiation based on aggregation-induced emission

A new sensitive fluorescence turn-on detection of gamma-radiation is reported by taking advantage of AIE property of the tetraphenylethylene unit and the cascade radiochemical and protonation reactions.</p

Transport Structure of the South Atlantic Ocean Derived From a High-Resolution Numerical Model and Observations

The South Atlantic Ocean plays an important role in the Atlantic meridional overturning circulation (AMOC), connecting it to the Indian and Pacific Oceans as part of the global overturning circulation system. Yet, there are still open questions regarding the relative importance of the warm water versus cold water sources in the upper limb of the AMOC and on the detailed circulation pathways of the North Atlantic Deep Water (NADW) in the lower limb. These questions are addressed using model outputs from a 60-year, eddying global ocean-sea ice simulation that are validated against observations. We find that the Pacific Antarctic Intermediate Water (AAIW) plays a role in setting the temperature and salinity properties of the water in the subtropical South Atlantic, but that the upper limb of the AMOC originates primarily from the warm Indian water through the Agulhas leakage (9.8 Sv of surface water + 3.5 of AAIW) and that only a relatively small contribution of 1.5 Sv colder, fresher AAIW originates from the Pacific Ocean. In the lower limb, the NADW flows southward as a deep western boundary current all the way to 45°S and then turns eastward to flow across the Mid-Atlantic Ridge near 42°S before leaving the Atlantic Ocean, although there is clockwise recirculation in the Brazil, Angola, and Cape Basins.</jats:p

Rice<i>TSV2</i>encoding threonyl-tRNA synthetase is needed for early chloroplast development and seedling growth under cold stress

AbstractThreonyl-tRNA synthetase (ThrRS), one of the aminoacyl-tRNA synthetases (AARSs), plays a crucial role in protein synthesis. However, the AARS functions on rice chloroplast development and growth were not fully appraised. In this study, a thermo-sensitive virescent mutant tsv2, which showed albino phenotype and lethal after the 4-leaf stage at 20°C but recovered to normal when the temperatures rose, was identified and characterized. Map-based cloning and complementation tests showed that TSV2 encoded a chloroplast-located ThrRS protein in rice. The Lys-to-Arg mutation in the anticodon-binding domain hampered chloroplast development under cold stress, while the loss of function of the ThrRS core domain in TSV2 fatally led to seedling death regardless of growing temperatures. In addition, TSV2 had a specific expression in early leaves. Its disruption obviously resulted in the downregulation of certain genes associated with chlorophyll biosynthesis, photosynthesis, and chloroplast development at cold conditions. Our observations revealed that rice nuclear-encoded TSV2 plays an important role in chloroplast development at the early leaf stage under cold stress.</jats:p