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The saltwater intrusion occurs in many coastal areas worldwide and has become a serious menace to freshwater quality. In the Pearl River estuary, saltwater intrusion has threatened the water supply for residential, agricultural, and industrial uses in the past decades, resulting in ecological and economic losses. In this study, the observed saltwater intrusion records of 10 years (2012 ~ 2021) at 9 stations in the Modaomen waterway, the largest inlet of the Pearl River estuary, were compiled. The time duration of saltwater intrusion was analyzed rather than the traditional distance length, along with the reported annual sea level records and river discharge volumes. The annual duration of saltwater intrusion exhibits spatial variations and is inversely related to the distance from the the Pearl River estuary mouth. In the study area which is near the main estuary mouth of the Pearl River, results from a multiple linear regression show that the observed annual saltwater intrusion days near the main Pearl River estuary mouth could be quantitatively explained by the combination of river discharge (dominant) and relative sea level. This work presents an example to investigate the combined river discharge and sea level impact on saltwater intrusion with annually compiled observed data and from a time-change perspective. [ABSTRACT FROM AUTHOR]

Bioelectronic medicine is a rapidly growing field where targeted electrical signals can act as an adjunct or alternative to drugs to treat neurological disorders and diseases via stimulating the peripheral nervous system on demand. However, current existing strategies are limited by external battery requirements, and the injury and inflammation caused by the mechanical mismatch between rigid electrodes and soft nerves. Here we report a wireless, leadless, and battery-free ferroelectret implant, termed NeuroRing, that wraps around the target peripheral nerve and demonstrates high mechanical conformability to dynamic motion nerve tissue. As-fabricated NeuroRing can act as an ultrasound receiver that converts ultrasound vibrations into electrostimulation pulses, thus stimulating the targeted peripheral nerve on demand. This capability is demonstrated by the precise modulation of the sacral splanchnic nerve to treat colitis, providing a framework for future bioelectronic medicines that offer an alternative to non-specific pharmacological approaches. Neurostimulators are often bulky and uncomfortable. Researchers report a wireless, leadless, and battery-free ultrasound receiver that wraps around the target peripheral nerve and allows precise modulation of organ function, providing a framework for future bioelectronic medicines [ABSTRACT FROM AUTHOR]

To solve the problem that twist springback of thin-walled component with asymmetric complex section cannot meet the high-precision quality requirement, FEA (finite element analysis) model of multi-pass roll forming (RF) process is established. Different material constitutive models are verified with RF tests, and the developed FEA model with variable elastic modulus and Yld2000 yield criterion is carried out to predict twist springback accurately. The mechanism of twist springback is studied by numerical simulations that twist springback results from the torque produced with the uneven residual longitudinal stress distribution due to the asymmetric forming for asymmetric section. The effect of different forming strategies on twist springback is discussed that developed UDT-type (USTB-Durable T) method with constant-arc-length method can effectively control twist springback. Orthogonal test is designed to study the effect of process parameters on twist springback. Results indicate that forming stands has the greatest impact on twist angle, followed by roll diameter and inter-distance, and roll gap has the smallest impact. The developed design and forming parameters are applied to control twist springback of asymmetric complex-section product. The actual product is deformed in industrial production line with the twist angle of less than 2 ∘ / m to meet high-precise quality requirement. [ABSTRACT FROM AUTHOR]

In view of the problems of poor flexibility of conventional roll forming of circular tubes, the UDF (USTB-Durable F) flexible roll forming method was used to model and simulate five kinds of thin-walled circular tubes with different thicknesses and the same outer diameter, so as to verify the applicability of UDF flexible roll forming method. In order to realize the commonality of UDF rolls, according to the roll positions of seven kinds of thin-walled circular tubes with different outer diameters and thicknesses within the specification range, mathematical models between tube specifications and corresponding roll position parameters were established. Combined with the actual parameters of the thin-walled circular tube roll forming unit, the UDF forming process suitable for the flexible forming of thin-walled circular tubes was obtained and compared with the conventional process by finite element simulation. Results show that the edge molding quality of the UDF process is better than that of the conventional process, and the amount of springback is less and the accuracy of the outer diameter of the section is high. The establishment of the roll position mathematical model and the special process parameters of the UDF flexible roll forming method provides a reference for the development of flexible production of roll forming of circular tubes. [ABSTRACT FROM AUTHOR]

Invasive electrical stimulation (iES) is prone to cause neural stimulus-inertia owing to its excessive accumulation of exogenous charges, thereby resulting in many side effects and even failure of nerve regeneration and functional recovery. Here, a wearable neural iES system is well designed and built for bionic and long-lasting neural modulation. It can automatically yield biomimetic pulsed electrical signals under the driven of respiratory motion. These electrical signals are full of unique physiological synchronization can give biofeedback to respiratory behaviors, self-adjusting with different physiological states of the living body, and thus realizing a dynamic and biological self-matched modulation of voltage-gated calcium channels on the cell membrane. Abundant cellular and animal experimental evidence confirm an effective elimination of neural stimulus-inertia by these bioelectrical signals. An unprecedented nerve regeneration and motor functional reconstruction are achieved in long-segmental peripheral nerve defects, which is equal to the gold standard of nerve repair -- autograft. The wearable neural iES system provides an advanced platform to overcome the common neural stimulus-inertia and gives a broad avenue for personalized iES therapy of nerve injury and neurodegenerative diseases. Designing wereable neural invasive electrical stimulation system remains a challenge. Here, researchers provide an effective technology platform for the elimination of tricky neural stimulus-inertia using bionic electronic modulation, which is a significant step forward for long-lasting treatment of nervous system diseases. [ABSTRACT FROM AUTHOR]

Surface reconstructed SrTiO3 nanocrystals were synthesized by a thermal treatment process in presence of NaBH4 and SrTiO3 nanocrystals. The surface reconstruction of SrTiO3 nanocrystals is attributed to the introduction of surface oxygen vacancies or Ti sites (such as Ti3+ and Ti2+) during the hydrogenation treatment process. The light absorption and the charge transfer ability of SrTiO3 nanocrystals are simultaneously enhanced due to surface oxygen vacancies or Ti sites (such as Ti3+ and Ti2+), which are beneficial to photocatalytic water splitting. Meanwhile, these defects also change the redox potential of the photocatalysts. Since there existed a synergistic effect between the three, the ratio of hydrogen to oxygen production was also regulated. [ABSTRACT FROM AUTHOR]