Recent Progress for Gallium-Based Liquid Metal in Smart Wearable Textiles

The development of smart textiles has presentend new requirements for integrated devices that can be compatible with both conductivity and deformation.At room temperature,liquid metal presents both metallic properties and flexible properties,as well as low toxicity and biocompatible,which makes it more and more popular on the research of liquid metal based electronic devices.This review summarizes the basic physical properties,and the key points to be fabricated into fibers and fabrics including oxides and wettability.Meantime,the application in the field of textiles is presented.Liquid metal based electrical conductive fibers and flexible sensors can be fabricated mainly by injection and printing,as well as direct-writing for smart fabrics.Liquid metal can be integrated as functional components for smart wearable devices in the future by assembling the as-prepared fibers and fabrics with textile technology,such as twisting,sewing,knitting,and embroidering.

The Marketing Factors Affecting Customer Decision-Making of Xiaomi Smart Wearable Devices in Guangxi,China

From an empirical point of view,this paper proposes research hypotheses and models based on the market situation of Xiaomi smart wearable devices in Guangxi,as well as the research status of consumers’purchasing decisions,combined with the empirical research of some researchers.This paper designs questionnaires and scales.The sampling survey method is used to investigate and analyze the influencing factors of Guangxi consumers’decision to purchase Xiaomi smart wearable devices.Questionnaires were distributed through Questionnaire Star,and 385 valid questionnaires were collected for descriptive statistics and correlation analysis.Conclusions are as follow:(1)Consumers in Guangxi who purchase Xiaomi smart wearable devices are between 19 and 32 years old,and most of them have a bachelor’s degree.Among the five factors of demographic characteristics,only income and marketing mix satisfaction have a positive correlation,indicating that customers are sensitive to Xiaomi smart wearable products.And among the customers of Xiaomi smart wearable products,the monthly income of less than 5,000 yuan accounted for 30.91%of the total number of surveys;the monthly income was 5,000-7,000 yuan,accounting for 34.29%.(2)The satisfaction of the marketing mix is positively correlated with the satisfaction of customer decision-making.The satisfaction of the marketing mix varies with the age,gender,education,income,and working years of each population,and only the income is positively correlated with the satisfaction of the marketing mix.Relationships,age,gender,education,and years of employment were not associated with marketing mix satisfaction.According to the above conclusions,relevant and reasonable product development and marketing suggestions are put forward for the enterprise,which provides a reference for the enterprise’s brand building and market development.Therefore,on the basis of comparing with other scholars at home and abroad,through the 7P marketing theory and purchasing decision theory and the research on the current situation of influencing factors for customers to purchase Xiaomi smart wearable devices in Guangxi,this paper compiled a questionnaire for 385 private colleges and universities in Guangxi.A questionnaire survey was carried out with customers,and the current situation of customers’purchasing decision-making behavior was obtained and analyzed and the following suggestions were put forward:continuously innovating products,targeting target customers,reasonably setting product prices,improving marketing mix.

Advanced Design of Fibrous Flexible Actuators for Smart Wearable Applications

Smart wearables equipped with integrated flexible actuators possess the ability to autonomously respond and adapt to changes in the environment.Fibrous textiles have been recognised as promising platforms for integrating flexible actuators and wearables owing to their superior body compliance,lightweight nature,and programmable architectures.Various studies related to textile actuators in smart wearables have been recently reported.However,the review focusing on the advanced design of these textile actuator technologies for smart wearables is lacking.Herein,a timely and thorough review of the progress achieved in this field over the past five years is presented.This review focuses on the advanced design concepts for textile actuators in smart wearables,covering functional materials,innovative architecture configurations,external stimuli,and their applications in smart wearables.The primary aspects focus on actuating materials,formation techniques of textile architecture,actuating behaviour and performance metrics of textile actuators,various applications in smart wearables,and the design challenges for next-generation smart wearables.Ultimately,conclusive perspectives are highlighted.

Wearable Smart Sensor System for Medical Monitoring with an Assessment of the Level of Blood Loss and Pain Shock Because of Trauma or Injury

Blood loss in peacetime is mainly due to the normal menstrual cycle in women or diseases with surgical intervention. In wartime, blood loss in military personnel is a characteristic sign of a closed or open injury of the body during internal or external bleeding. Access to clinical care for wounded military personnel injured on the battlefield is limited and has long delays compared to patients in peacetime. Most of the deaths of wounded military personnel on the battlefield occur within the first hour after being wounded. The most common causes are delay in providing medical care, loss of time for diagnosis, delay in stabilization of pain shock and large blood loss. Some help in overcoming these problems is provided by the data in the individual capsule, which each soldier of the modern army possesses;however, data in an individual capsule is not sufficient to provide emergency medical care in field and hospital conditions. This paper considers a project for development of a smart real-time monitoring wearable system for blood loss and level of shock stress in wounded persons on the battlefield, which provides medical staff in field and hospital conditions with the necessary information to give timely medical care. Although the hospital will require additional information, the basic information about the victims will already be known before he enters the hospital. It is important to emphasize that the key term in this approach is monitoring. It is tracking, and not a one-time measurement of indicators, that is crucial in a valid definition of bleeding.

A Double-Compensation-Based Federated Learning Scheme for Data Privacy Protection in a Social IoT Scenario

Nowadays,smart wearable devices are used widely in the Social Internet of Things(IoT),which record human physiological data in real time.To protect the data privacy of smart devices,researchers pay more attention to federated learning.Although the data leakage problem is somewhat solved,a new challenge has emerged.Asynchronous federated learning shortens the convergence time,while it has time delay and data heterogeneity problems.Both of the two problems harm the accuracy.To overcome these issues,we propose an asynchronous federated learning scheme based on double compensation to solve the problem of time delay and data heterogeneity problems.The scheme improves the Delay Compensated Asynchronous Stochastic Gradient Descent(DC-ASGD)algorithm based on the second-order Taylor expansion as the delay compensation.It adds the FedProx operator to the objective function as the heterogeneity compensation.Besides,the proposed scheme motivates the federated learning process by adjusting the importance of the participants and the central server.We conduct multiple sets of experiments in both conventional and heterogeneous scenarios.The experimental results show that our scheme improves the accuracy by about 5%while keeping the complexity constant.We can find that our scheme converges more smoothly during training and adapts better in heterogeneous environments through numerical experiments.The proposed double-compensation-based federated learning scheme is highly accurate,flexible in terms of participants and smooth the training process.Hence it is deemed suitable for data privacy protection of smart wearable devices.

High-performance textile piezoelectric pressure sensor with novel structural hierarchy based on ZnO nanorods array for wearable application

With the increasing demand for smart wearable clothing, the textile piezoelectric pressure sensor (T-PEPS) that can harvest mechanical energy directly has attracted significant attention. However, the current challenge of T-PEPS lies in remaining the outstanding output performance without compromising its wearing comfort. Here, a novel structural hierarchy T-PEPS based on the single-crystalline ZnO nanorods are designed. The T-PEPS is constructed with three layers mode consisting of a polyvinylidene fluoride (PVDF) membrane, the top and bottom layers of conductive rGO polyester (PET) fabrics with self-orientation ZnO nanorods. As a result, the as-fabricated T-PEPS shows low detection limit up to 8.71 Pa, high output voltage to 11.47 V and superior mechanical stability. The sensitivity of the sensor is 0.62 V·kPa−1 in the pressure range of 0–2.25 kPa. Meanwhile, the T-PEPS is employed to detect human movements such as bending/relaxation motion of the wrist, bending/stretching motion of each finger. It is demonstrated that the T-PEPS can be up-scaled to promote the application of wearable sensor platforms and self-powered devices.

Dried bonito flakes-inspired moisture-responsive actuator with a gradient structure for smart devices

Exploring high-performance soft actuators from biomass resources is significant for developing eco-friendly smart devices.Dried bonito(DB)flake is a common food as well as a biomass material,and it can produce irregular motion in changed moisture,just like dancing.Inspired by this intriguing phenomenon,a cost-effective,biocom patible,and biodegradable moisture-responsive DB film actuator with a gradient structure is developed.The DB film actuator exhibits rapid and reversible bending deformation triggered by a humidity gradient with a high bending speed(40°s-1)and a maximum bending angle(180°).More-over,the DB film actuator shows large bending deformation(-71°to+51°)with a high actuation force(214.7 Pa)in response to changes in relative humidity.Furthermore,the actuation performance can be also tuned by adjusting the thickness of the film.Potential applications of this actuator,including smart grippers,crawling robots,and biomimetic flowers for visible humidity sensing,are demonstrated.More importantly,smart sweat-responsive wearables that automatically deform to promote sweat evaporation and convection during exercise are constructed based on the actuator,making it promising for adaptive personal thermal management.This work offers an easily processable,cost-effective,and environmentally benign strategy to construct moisture-responsive actuators for future eco-friendly smart devices.

Wearable and humidity-resistant biomaterials-based triboelectric nanogenerator for high entropy energy harvesting and self-powered sensing

Triboelectric nanogenerator(TENG)provides a new solution to the energy supply by harvesting high entropy energy.However,wearable electronic devices have high requirements for flexible,humidity-resistant,and low-cost TENG.Here,environmentfriendly and multi-functional wheat starch TENG(S-TENG)was made by a simple and green method.The open-circuit voltage and short-circuit current of S-TENG are 151.4 V and 47.1μA,respectively.S-TENG can be used not only to drive and intelligently control electronic equipment,but also to effectively harvest energy from body movements and wind.In addition,the output of S-TENG was not negatively affected with the increase in environmental humidity,but increased abnormally.In the range of 20%RH–80%RH,S-TENG can be potentially used as a sensitive self-powered humidity sensor.The S-TENG paves the way for large-scale preparation of multi-functional biomaterials-based TENG,and practical application of self-powered sensing and wearable devices.

A review on structures,materials and applications of stretchable electrodes

With the rapid development of wearable smart devices,many researchershave carried out in-depth research on the stretchable electrodes.As one of the corecomponents for electronics,the electrode mainly transfers the electrons,which plays animportant role in driving the various electrical devices.The key to the research for thestretchable electrode is to maintain the excellent electrical properties or exhibit theregular conductive change when subjected to large tensile deformation.This articleoutlines the recent progress of stretchable electrodes and gives a comprehensiveintroduction to the structures,materials,and applications,including supercapacitors,lithium-ion batteries,organic light-emitting diodes,smart sensors,and heaters.Theperformance comparison of various stretchable electrodes was proposed to clearly showthe development challenges in this field.We hope that it can provide a meaningfulreference for realizing more sensitive,smart,and low-cost wearable electrical devices inthe near future.