Based on first-principle,the geometric structures of intrinsic SnS2 and SnS2 doped with Ti atom replacing Sn atom were constructed,and the adsorption characteristics of five gases,namely CO,NO2,NO,SO2 and NH3 on the surfaces of the two materials were analyzed.Three adsorption sites were tested for each gas molecule and the best adsorption site was determined.The adsorption energy,transfer charge,recovery time,density of states and work function were researched to understand the adsorption mechanism.It is found that the adsorption capacities of CO and SO2 on the intrinsic SnS2 are weaker,while the adsorption capacities of NO,NO2 and NH3 on the intrinsic SnS2 are stronger.The structure of SnS2 doped by Ti atom replacing Sn atom is relatively stable,and its formation energy is-8.028 eV.At the same time,the adsorption energies of the five gas molecules on their surfaces increase to different degrees.The results show that SnS2 doped by Ti atom replacing Sn atom can improve the gas adsorption performance of SnS2 material,and its preparation method is practical,so it can be considered as a material for making gas sensors.
In this study, a flexible capacitive pressure sensor was developed, featuring a dielectric layer composed of a polydimethylsilane (PDMS)/BaTiO3/SrTiO3 3 /SrTiO 3 composite material. The electrode and dielectric layers were structured with a dual microstructure, combining diagonal and sandpaper-porous elements. Additionally, nano- barium titanate (BT) powder, known for its relatively high dielectric constant, was incorporated into PDMS, along with an appropriate amount of strontium titanate (STO), to enhance the sensor's sensitivity. The developed sensor exhibited a remarkable sensitivity of 2.681 kPa-1, -1 , with response and release times of approximately 39 ms and 61 ms, respectively. It demonstrated a low detection threshold and withstood over 5000 compression cycles, showcasing excellent repeatability. The results underscored the sensor's robust pressure-sensing performance, making it suitable for diverse applications, including human pulse monitoring, heartbeat tracking, robot arm sensing, object weight detection, and real-time healthcare monitoring.
Real-time DOA (direction of arrival) estimation of surface or underwater targets is of great significance to the research of marine environment and national security protection. When conducting real-time DOA estimation of underwater targets, it can be difficult to extract the prior characteristics of noise due to the complexity and variability of the marine environment. Therefore, the accuracy of target orientation in the absence of a known noise is significantly reduced, thereby presenting an additional challenge for the DOA estimation of the marine targets in real-time. Aiming at the problem of real-time DOA estimation of acoustic targets in complex environments, this paper applies the MEMS vector hydrophone with a small size and high sensitivity to sense the conditions of the ocean environment and change the structural parameters in the adaptive adjustments system itself to obtain the desired target signal, proposes a signal processing method when the prior characteristics of noise are unknown. Theoretical analysis and experimental verification show that the method can achieve accurate real-time DOA estimation of the target, achieve an error within 3.1° under the SNR (signal-to-noise ratio) of the X channel of −17 dB, and maintain a stable value when the SNR continues to decrease. The results show that this method has a very broad application prospect in the field of ocean monitoring.
Bone homeostasis is based on the dynamic balance of bone formation and bone resorption. An imbalance in bone homeostasis is a major contributor to many skeletal diseases, including osteoporosis. Changes in the composition and diversity of the gut microbiota (GM) are supposed to have a significant impact on bone homeostasis and are closely correlated with changes in bone mass and bone microarchitecture. The "gut-immune" axis, which is formed by the interaction between the host intestinal immune system and GM, is essential for maintaining bone homeostasis, as well as regulating the body's immunological response and maintaining immune homeostasis throughout the intestine and body. The article reviews recent advances in the study of GM, the immune system, and their synergistic impact on bone homeostasis.
Nitrocellulose microspheres have garnered extensive use in propellants and launching agents due to their inherent safety, robust flowability, and high explosive power. However, conventional preparation methods for these microspheres are often hampered by complex processes, low safety factor and poor sphericity. This study explores an innovative approach to nitrocellulose microsphere fabrication utilizing microfluidic technology. We designed and assembled two high-throughput preparation devices-a coaxial and a centrifugal device-employing 3D printing technology. Our findings demonstrate an 18-fold increase in efficiency over traditional single-pass microfluidic techniques. Additionally, we examined the impact of these devices on the microspheres' size distribution. The proposed device showcases significant advantages, including reduced cost, enhanced efficiency, and shorter production cycles, indicating promising potential for wide-scale application in nitrocellulose microsphere preparation.
