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A novel MXene/cadmium azide nanocomposite with a low input energy and high output power is designed by self-assembly of Cd ions on the MXene layers and subsequent in situ azidation in a solution reaction. The research result shows that cadmium azide nanoparticles with a uniform size of ∼50 nm are well dispersed on the MXene nanosheet’s surface, which is benefited from the rich functional groups on the MXene surface that can effectively immobilize and prevent the aggregation of the nanoparticles through electrostatic interaction. The thermal decomposition temperature (378.42 °C) and crystal structure of cadmium azide show no noticeable change after hybridizing with the MXene; more positively, the required input energy of the MXene/cadmium azide nanocomposite is significantly reduced, which is verified by its electric initiation input voltage of just 4.65 V. In addition, detonation can be realized by loading a less amount of the MXene/cadmium azide nanocomposite. These results demonstrate that the MXene/cadmium azide nanocomposite has the potential to be used as detonators in high-temperature environments.

Abstract The search for topological superconductivity (TSC) is currently an exciting pursuit, since non-trivial topological superconducting phases could host exotic Majorana modes. However, the difficulty in fabricating proximity-induced TSC heterostructures, the sensitivity to disorder and stringent topological restrictions of intrinsic TSC place serious limitations and formidable challenges on the materials and related applications. Here, we report a new type of intrinsic TSC, namely intrinsic surface topological superconductivity (IS-TSC) and demonstrate it in layered AuSn4 with T c of 2.4 K. Different in-plane and out-of-plane upper critical fields reflect a two-dimensional (2D) character of superconductivity. The two-fold symmetric angular dependences of both magneto-transport and the zero-bias conductance peak (ZBCP) in point-contact spectroscopy (PCS) in the superconducting regime indicate an unconventional pairing symmetry of AuSn4. The superconducting gap and surface multi-bands with Rashba splitting at the Fermi level (E F ), in conjunction with first-principle calculations, strongly suggest that 2D unconventional SC in AuSn4 originates from the mixture of p-wave surface and s-wave bulk contributions, which leads to a two-fold symmetric superconductivity. Our results provide an exciting paradigm to realize TSC via Rashba effect on surface superconducting bands in layered materials.

Electronic products are subjected to thermal cycling caused by power cycling in service processes. Owing to the difference in the coefficients of thermal expansion (CTEs) of solder joints and other packaging materials, solder joints suffer from thermomechanical fatigue, and cracks appear at their bonding interfaces. Solder joints are usually a single grain or three grains with Beachball morphology, and their composition is Sn-based Pb-free SAC305 (96.5Sn–3.0Ag–0.5Cu wt.%) solder, which exhibits obvious anisotropic mechanical behavior. This study investigated a thermal cycling simulation of Plastic Ball Grid Array (PBGA) packaging, in which the Anand model was used for solder joints, and the outermost solder joint was found to be a dangerous point. Sub-models were then established for this solder joint with several typical crystal orientations. The effect of crystal orientation under thermal cycling was simulated using thermomechanical crystal plasticity. When the c-axis of Sn crystal was perpendicular to the substrate, the deformation resistance was the largest, and the accumulation of equivalent plastic strain and strain energy dissipation was the slowest; hence, the fatigue life was the longest. As the angle between the c-axis and the substrate decreased, the deformation accumulated faster. When the c-axis was parallel to the substrate, the deformation of the solder joint was the fastest, and thus this joint was the first to fail and had the shortest fatigue life. In addition, the simulation of three grains indicated that orientations and their distributions had an influence on the shear strain accumulation of slip systems and fatigue life.

Koumiss, a traditional fermented dairy product made from fresh mare milk, is a sour beverage that contains an abundance of microbial communities, including lactic acid bacteria, yeast and others. Firstly, probiotics such as Lacticaseibacillus in koumiss can induce the secretion of immunoglobulin G in serum and interleukin-2 in the spleen while beneficial Saccharomyces can secrete antibacterial compounds such as citric acid and ascorbic acid for specific immunopotentiation. Additionally, more isoflavone in koumiss can regulate estrogen levels by binding to its receptors to prevent breast cancer directly. Bile salts can be converted into bile acids such as taurine or glycine by lactic acid bacteria to lower cholesterol levels in vivo. Butyric acid secretion would be increased to improve chronic gastrotis by regulating intestinal flora with lactic acid bacteria. Finally, SCFA and lCFA produced by Lacticaseibacillus inhibit the reproduction of pathogenic microorganisms for diarrhea prevention. Therefore, exploring the mechanisms underlying multiple physiological functions through utilizing microbial resources in koumiss represents promising avenues for ameliorating chronic diseases.

Solar spicules are small-scale jet-like structures in the lower solar atmosphere. Currently, the formation of these widely distributed structures lacks a complete explanation. It is still unclear whether they play an essential role in corona heating. Here, based on the magnetohydrodynamic scaling transformation relation, we perform experiments with the interaction of a high power laser with a one-dimensional sinusoidal modulated target to model solar spicules. We observe several spicule-like structures with alternating polarity magnetic fields around them. Magnetohydrodynamic simulations with similar parameters show the detail information during the spicules’ formation. The results suggest that the so-called strong pulse model can lead to the formation of the solar spicules. The magnetic reconnection process may also play a part and lead to additional heating and brightening phenomena.

ObjectiveThe study aimed to investigate the effects of a 12-week Tai Chi exercise intervention on working memory in older adults using ERP-fNIRS.MethodFifty older adults were randomly assigned to either an experimental group receiving a 12-week Tai Chi exercise intervention or a control group receiving regular daily activities. Working memory was assessed using the n-back task before and after the intervention, and spatial and temporal components of neural function underlying the n-back task were measured using ERP-fNIRS.ResultsThe experimental group demonstrated significant improvements in reaction time and accuracy on the 2-back task and showed higher activation levels in the R-DLPFC. Additionally, the Tai Chi group displayed significant increases in P3 amplitude in the overall n-back task.ConclusionThese findings suggest that Tai Chi interventions can enhance working memory in older adults, as evidenced by increasing neural activity and improving HbO in the R-DLPFC during the 2-back task.

Abstract Objective To verify the reliability and validity of the simplified Chinese version of the Yale Physical Activity Survey (YPAS) scale in the measurement of physical activity of elderly women in mainland China to provide a new standardized scale for evaluating the level of physical activity. Methods Twenty-one healthy elderly women completed all the research procedures. The participants completed the questions on the YPAS and wore an Omegawave Sport Technology®System diagnostic system that recorded maximum oxygen uptake and the adaptation index of the energy metabolism system. The reliability of the YPAS was evaluated based on the consistency of the two measurements (pre-test and post-test), and its validity was verified based on the relevant indicators in the Omegawave diagnostic system. Descriptive statistics, intraclass correlation coefficient and Pearson correlation analysis were used. The significance level was set at p

BackgroundTai Chi Chuan (TCC) is an effective method for delaying cognitive decline in older adults. However, in older adults, the association between long-term TCC practice and working memory updating has not been extensively studied.ObjectiveThis cross-sectional study investigated how updating function operationalized via Reaction Times (RTs) and Accuracy Rates (ARs) of N-Back tasks being measured in a laboratory setting is related to long term practice of TCC.MethodsTwenty-six healthy elderly people participated in this experiment. According to the duration of time TCC was practiced, 13 subjects in the TCC group had more than 5 years of experience with TCC exercise, and 13 elderly subjects who had not been systematically exposed to mind-body exercise were assigned to the control group. The N-back task was administered to every participant to evaluate the updating function.ResultsThe TCC group had faster RTs than the control group (p < 0.05). For the 1-back task, the TCC group showed faster RTs than the control group; for the 2-back task, the TCC group exhibited faster RTs than the control group. The TCC group had higher ARs than the control group (p < 0.05). For the 1-back task, the TCC group showed higher ARs than the control group; for the 2-back task, the TCC group exhibited higher ARs than the control group.ConclusionsLong-term TCC practitioners exhibit a better updating function as compared to controls who did not practice TCC. Thus, our findings suggest that long-term TCC positively influences the updating function of older adults, making it, in turn, an effective mind-body exercise to maintain specific aspects of cognitive functioning.

The Zeeman splitting effect is observed in a strong magnetic field generated by a laser-driven coil. The expanding plasma from the coil wire surface is concentrated at the coil center and interacts with the simultaneously generated magnetic field. The Cu I spectral lines at wavelengths of 510.5541, 515.3235, and 521.8202 nm are detected and analyzed. The splittings of spectral lines are used to estimate the magnetic field strength at the coil center as ∼31.4 ± 15.7 T at a laser intensity of ∼5.6 × 1015 W/cm2, which agrees well with measurements using a B-dot probe. Some other plasma parameters of the central plasma disk are also studied. The temperature is evaluated from the Cu I spectral line intensity ratio, while the electron density is estimated from the Stark broadening effect.

We used long-term data on the variation in harem size in Yunnan snub-nosed monkeys to research the effects of harem size on reproductive success and the ratio of grooming received to given (RGRG). The results suggest that harem holders derive reproductive benefits commensurate with harem size, whereas the females’ reproductive success is unaffected by harem size. Males of larger harems groomed less and had higher RGRG than males of smaller harems. In the case of females, grooming given increased, and RGRG decreased with an increase in harem size. The males’ reproductive success seems to be a driver of harem size maximization. From the females’ perspective, dwindling social benefits appear to set the upper limit for harem enlargement. We also showed that males of monogamous units (‘single-female harems’) invested more into grooming their female, presumably to prevent unit disintegration and loss of mating privileges.

Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive brain-stimulation technique that transiently modulates cerebral cortex excitability, achieving overall positive results in poststroke motor-function recovery. Excessive inhibition of the ipsilesional-affected hemisphere by the contralesional-unaffected hemisphere has seriously hindered poststroke motor-function recovery. Hence, intracortical disinhibition can be used as an approach to managing poststroke brain injury. This technique promotes neural plasticity for faster motor-function recovery. rTMS relieves unilateral inhibition of the brain function by regulatinga interhemispheric-imbalanced inhibition. This paper summarized 12 studies from 2016 to date, focusing on rTMS on motor function after acute and chronic stroke by regulating the interhemispheric imbalance of inhibitory inputs. Although rTMS studies have shown promising outcomes on recovery of motor functions in stroke patients, different intervention methods may lead to discrepancies in results. A uniform optimal stimulus model cannot routinely be used, mainly due to the stimulus schemes, stroke types and outcome-measuring differences among studies. Thus, the effect of rTMS on poststroke motor-function recovery should be investigated further to standardize the rTMS program for optimal poststroke motor-function recovery. More randomized, placebo-controlled clinical trials with standardized rTMS protocols are needed to ensure the effectiveness of the treatment.

A double-turn capacitor-coil is used to produce a magnetic field (38.5 T) and construct a topology of magnetic reconnection in a low-β (β < 1) plasma environment. The device is constructed with two metallic U-turn coils connecting two parallel metallic disks. High energy lasers are employed to ablate one disk spontaneously driving two currents in the two coils, which produces an interactive magnetic field topology. We demonstrated through experiments and numerical simulations that the reconnection process takes place between two non-uniform magnetic fields created by the coils, and that the plasma state and the associated magnetic topology in the process can be seen via the technology of the optical probe beam and the proton backlight. [ABSTRACT FROM AUTHOR]

A counter-streaming flow system is a test-bed to investigate the astrophysical collisionless shock (CS) formation in the laboratory. Electrostatic/electromagnetic instabilities, competitively growing in the system and exciting the CS formation, are sensitive to the flows parameters. One of the most important parameters is the velocity, determining what kind of instability contributes to the shock formation. Here we successfully measure the evolution of the counter-streaming flows within one shot using a multi-pulses imaging diagnostic technique. With the technique, the average velocity of the high-density-part () of the flow is directly measured to be of cm/s between 7 ns and 17 ns. Meanwhile, the average velocity of the low-density-part () can be estimated as cm/s. The experimental results show that a collisionless shock is formed during the low-density-part of the flow interacting with each other. [ABSTRACT FROM AUTHOR]