Explore the vast range of titles available.

Wearable health monitoring systems have gained considerable interest in recent years owing to their tremendous promise for personal portable health watching and remote medical practices. The sensors with excellent flexibility and stretchability are crucial components that can provide health monitoring systems with the capability of continuously tracking physiological signals of human body without conspicuous uncomfortableness and invasiveness. The signals acquired by these sensors, such as body motion, heart rate, breath, skin temperature and metabolism parameter, are closely associated with personal health conditions. This review attempts to summarize the recent progress in flexible and stretchable sensors, concerning the detected health indicators, sensing mechanisms, functional materials, fabrication strategies, basic and desired features. The potential challenges and future perspectives of wearable health monitoring system are also briefly discussed.

The discovery of natural adhesion phenomena and mechanisms has advanced the development of a new generation of tissue adhesives in recent decades. In this study, we develop a natural biological adhesive from snail mucus gel, which consists a network of positively charged protein and polyanionic glycosaminoglycan. The malleable bulk adhesive matrix can adhere to wet tissue through multiple interactions. The biomaterial exhibits excellent haemostatic activity, biocompatibility and biodegradability, and it is effective in accelerating the healing of full-thickness skin wounds in both normal and diabetic male rats. Further mechanistic study shows it effectively promotes the polarization of macrophages towards the anti-inflammatory phenotype, alleviates inflammation in chronic wounds, and significantly improves epithelial regeneration and angiogenesis. Its abundant heparin-like glycosaminoglycan component is the main active ingredient. These findings provide theoretical and material insights into bio-inspired tissue adhesives and bioengineered scaffold designs. Natural adhesives have received a lot of attention recently. Here, the authors develop a natural biological adhesive from snail mucus that can adhere to wet tissue and be used to accelerate healing of skin wounds.

The gas-adsorption behaviors of small molecules CO, H 2 O, H 2 S, NH 3 , SO 2 , and NO on pristine penta-graphene (PG) were investigated using first-principles calculations to explore their potential for use as advanced gas-sensing materials. Results show that, except for CO, H 2 O, H 2 S, NH 3 , and SO 2 are physically adsorbed on the surface of penta-graphene with considerable adsorption energy and moderate charge transfer, while NO is prone to be chemically adsorbed on the surface of penta-graphene. Moreover, the electronic properties of PG can be effectively modified after H 2 O, H 2 S, NH 3 , SO 2 , and NO are adsorbed, and penta-graphene has potential for using in gas sensors via the charge-transfer mechanism.

Ni3Al-based superalloys have excellent mechanical properties which have been widely used in civilian and military fields. In this study, the mechanical properties of the face-centred cubic structure Ni3Al were investigated by a first principles study based on density functional theory (DFT), and the generalized gradient approximation (GGA) was used as the exchange-correlation function. The bulk modulus, Young’s modulus, shear modulus and Poisson’s ratio of Ni3Al polycrystal were calculated by Voigt-Reuss approximation method, which are in good agreement with the existing experimental values. Moreover, directional dependences of bulk modulus, Young’s modulus, shear modulus and Poisson’s ratio of Ni3Al single crystal were explored. In addition, the thermodynamic properties (e.g., Debye temperature) of Ni3Al were investigated based on the calculated elastic constants, indicating an improved accuracy in this study, verified with a small deviation from the previous experimental value.

The field of piezoresistive sensors has been undergoing a significant revolution in terms of design methodology, material technology and micromachining process. However, the temperature dependence of sensor characteristics remains a hurdle to cross. This review focuses on the issues in thermal-performance instability of piezoresistive sensors. Based on the operation fundamental, inducements to the instability are investigated in detail and correspondingly available ameliorative methods are presented. Pros and cons of each improvement approach are also summarized. Though several schemes have been proposed and put into reality with favorable achievements, the schemes featuring simple implementation and excellent compatibility with existing techniques are still emergently demanded to construct a piezoresistive sensor with excellent comprehensive performance.

The longstanding demands for micropressure detection in commercial and industrial applications have led to the rapid development of relevant sensors. As a type of long-term favored device based on microelectromechanical system technology, the piezoresistive micropressure sensor has become a powerful measuring platform owing to its simple operational principle, favorable sensitivity and accuracy, mature fabrication, and low cost. Structural engineering in the sensing diaphragm and piezoresistor serves as a core issue in the construction of the micropressure sensor and undertakes the task of promoting the overall performance for the device. This paper focuses on the representative structural engineering in the development of the piezoresistive micropressure sensor, largely concerning the trade-off between measurement sensitivity and nonlinearity. Functional elements on the top and bottom layers of the diaphragm are summarized, and the influences of the shapes and arrangements of the piezoresistors are also discussed. The addition of new materials endows the research with possible solutions for applications in harsh environments. A prediction for future tends is presented, including emerging advances in materials science and micromachining techniques that will help the sensor become a stronger participant for the upcoming sensor epoch.

Selective inhibition of the intrinsic coagulation pathway is a promising strategy for developing safer anticoagulants that do not cause serious bleeding. Intrinsic tenase, the final and rate-limiting enzyme complex in the intrinsic coagulation pathway, is an attractive but less explored target for anticoagulants due to the lack of a pure selective inhibitor. Fucosylated glycosaminoglycan (FG), which has a distinct but complicated and ill-defined structure, is a potent natural anticoagulant with nonselective and adverse activities. Herein we present a range of oligosaccharides prepared via the deacetylation–deaminative cleavage of FG. Analysis of these purified oligosaccharides reveals the precise structure of FG. Among these fragments, nonasaccharide is the minimum fragment that retains the potent selective inhibition of the intrinsic tenase while avoiding the adverse effects of native FG. In vivo, the nonasaccharide shows 97% inhibition of venous thrombus at a dose of 10 mg/kg in rats and has no obvious bleeding risk. This nonasaccharide may therefore serve as a novel promising anticoagulant.

Electronics are becoming smaller and more versatile, and the size of solder joints has decreased to tens of microns, inducing obvious inhomogeneity among the phases in the solder matrix microstructure. In this study, the influence of phase inhomogeneity on the mechanical behavior of microscale Cu/Sn–58Bi/Cu solder joints was studied. Sn and Bi single-phase solid solution samples with the same composition as the Sn and Bi phases in the Sn58Bi microstructure were prepared, and their mechanical performances, elastic constants, and power-law constitutive models were measured, calculated, and identified. Based on the obtained mechanical performances, elastic constants, and power-law constitutive models, a three-dimensional finite element model of line-type Cu/Sn58Bi/Cu microscale solder joints, including their microstructure, was established. The results demonstrate that phase inhomogeneity increases the maximum value of von Mises stress, leading to stress concentration. When the Sn58Bi solder matrix transfers from the elastic deformation stage to the plastic deformation stage, the high σ eq zone of the matrix gradually shifts from the Sn phase to the Bi phase. In addition, a study of the anisotropy reveals that the elastic anisotropic mechanical properties of Sn58Bi solder matrix are mainly affected by the anisotropic effect of Sn. The stress concentration is the lowest when the crystal orientation is π/2.

For the reliability of cryoelectronics, the tensile performance and fracture behavior of microscale Cu/Sn3.0Ag0.5Cu/Cu joints with shrinking size were investigated at decreasing temperature ranging from 25 °C to −120 °C. The experimental results showed that the tensile behavior of solder joints was greatly influenced by temperature and joint size. The tensile strength of the solder joint increased with decreasing temperature. At a same temperature, the joint tensile strength increased with decreasing thickness-to-diameter ratio ( R  =  t/d , 1, 1/2 and 1/4). In addition, at a same R , the joint with a smaller diameter had a higher tensile strength. In general, the tensile strength showed an inversely proportional function of solder volume. Moreover, as temperature decreased, the fracture position changed from the solder matrix to the interface between solder and intermetallic compound layer, showing a ductile-to-brittle transition. The ductile-to-brittle transition temperature increased with decreasing R in the solder joints with a same diameter, and it decreased with decreasing joint diameter in the solder joints with a same R .

Applying BIM in the model of EPC General contracting, general contractor, designer, constructor, Supervisor and other professional sub contractors can share resource which can achieve the project information, standardization, visualization, collaborative and ultimately make the project quality, schedule, cost, safety and other objectives to achieve maximum.