Smart Cellulose‑Based Janus Fabrics with Switchable Liquid Transportation for Personal Moisture and Thermal Management

The Janus fabrics designed for personal moisture/thermal regulation have garnered significant attention for their potential to enhance human comfort.However,the development of smart and dynamic fabrics capable of managing personal moisture/thermal comfort in response to changing external environments remains a challenge.Herein,a smart cellulose-based Janus fabric was designed to dynamically manage personal moisture/heat.The cotton fabric was grafted with N-isopropylacrylamide to construct a temperature-stimulated transport channel.Subsequently,hydrophobic ethyl cellulose and hydrophilic cellulose nanofiber were sprayed on the bottom and top sides of the fabric to obtain wettability gradient.The fabric exhibits anti-gravity directional liquid transportation from hydrophobic side to hydrophilic side,and can dynamically and continuously control the transportation time in a wide range of 3–66 s as the temperature increases from 10 to 40℃.This smart fabric can quickly dissipate heat at high temperatures,while at low temperatures,it can slow down the heat dissipation rate and prevent the human from becoming too cold.In addition,the fabric has UV shielding and photodynamic antibacterial properties through depositing graphitic carbon nitride nanosheets on the hydrophilic side.This smart fabric offers an innovative approach to maximizing personal comfort in environments with significant temperature variations.

基于区块链和HACCP的水产品溯源系统

针对传统的水产品溯源中心化严重、数据易被篡改等问题,运用区块链技术,基于危害分析与关键控制点(HACCP)设计水产品溯源体系.采用多元线性回归的方法对样品数据指标进行处理,确认了养殖过程中的关键控制点;在确定关键信息的基础上,设计了智能合约对水产品溯源各环节的上传数据进行判定.从系统可行性出发,分别对系统功能、共识拓扑、溯源编码进行详细设计.搭建水产品溯源系统,并对系统的功能和性能进行了测试.结果表明:系统的交易吞吐量固定在320笔/s上下,平均交易延迟在0.5 s左右,交易成功率在99.8%左右,完全可以满足生产实践的需求.

一种面向联盟链Hyperledger Fabric的并发冲突事务优化方法

随着区块链技术应用的普及,联盟链Hyperledger Fabric(简称Fabric)已成为知名区块链开源平台,并得到广泛关注.然而Fabric仍受困于并发事务间冲突问题,冲突发生时会引发大量无效交易上链,导致吞吐量下降,阻碍其发展.对于该问题,现有面向块内冲突的方案缺乏高效的冲突检测和避免方法,同时现有研究往往忽略区块间冲突对吞吐量的不利影响.提出了一种Fabric的优化方案Fabric-HT(fabric with high throughput),从区块内和区块间2方面入手,有效降低事务间并发冲突和提高系统吞吐量.针对区块内事务冲突,提出了一种事务调度机制,根据块内冲突事务集定义了一种高效数据结构——依赖关系链,识别具有“危险结构”的事务并提前中止,合理调度事务和消除冲突;针对区块间事务冲突,将冲突事务检测提前至排序节点完成,建立以“推送-匹配”为核心的冲突事务早期避免机制.在多场景下开展大量实验,结果表明Fabric-HT在吞吐量、事务中止率、事务平均执行时间、无效事务空间占用率等方面均优于对比方案.Fabric-HT吞吐量最高可达Fabric的9.51倍,是最新优化方案FabricSharp的1.18倍;空间利用率上相比FabricSharp提升了14%.此外,Fabric-HT也表现出较好的鲁棒性和抗攻击能力.

基于Fabric的海量交易数据上链预处理机制

Hyperledger Fabric是一种国内外广泛使用的联盟链框架,在基于Fabric技术的一些业务中具有协同组织众多、交易操作频繁、事务冲突增加等特点。Fabric采用的多版本并发控制技术能够在一定程度上解决部分交易冲突,提升系统并发性,但其机制不完善,会出现部分交易数据无法正常上链存储的问题。为了实现海量交易数据完整、高效、可信的上链存储,提出一种基于Fabric预言机的数据上链预处理机制。设计海量数据冲突预处理(MCPP)方法,通过检测、监听、延时提交、事务加锁、重排序缓存等方式实现主键冲突交易数据的完整上链。引入数据传输保障措施,在传输过程中利用非对称加密技术防止恶意节点伪造认证信息,确保交易数据链外处理前后的一致性。通过理论分析和实验结果表明,该机制可有效解决联盟链平台中海量交易数据上链时的并发冲突问题,当交易数据规模达到1 000和10 000时,MCPP的时效性比LMLS提高了38%和21.4%,且成功率接近100%,具有高效性和安全性,同时在无并发冲突情况下不影响Fabric系统性能。

基于CP-ABE算法的Fabric隐私保护模型

传统区块链系统缺少对区块数据的隐私保护。结合CP-ABE(基于属性加密的密文策略)算法和IPFS(星际文件系统),提出一种可以对Fabric区块链实现访问控制的隐私保护模型CP-PPM。CP-PPM的数据所有者可以灵活设置访问控制策略。仿真结果表明,与现有Fabric区块链系统相比,CP-PPM模型支持细粒度的访问控制,具有更强的隐私保护效果;CP-ABE算法可以安全初始化,对数据的加解密效率更高,同时增强了区块链系统的存储性能。

生态流量监测系统的区块链框架设计及管理模块实现

河湖生态流量保障工作是全面推行河湖长制、实行最严格水资源管理制度的重要内容,确保生态流量监测数据在多部门流转过程中的可信与安全共享尤其重要。针对生态流量监测数据应用和共享的多样化、差异化、动态化需求,结合区块链技术的优点,在生态流量监测系统中引入Hyperledger Fabric平台的可插拔式区块链组件,构建了包含基础系统层、区块链中枢层、区块链服务支撑层、业务应用层的四层联盟链系统架构,围绕链上数据的可信安全共享及溯源需求,设计实现了区块链系统用户管理、数据及文件操作、区块链浏览三个功能模块,开发了区块链信息查看功能页面并集成至水库水情测报系统中。可插拔式区块链支撑组件的引入,便于对已建信息化平台进行区块链技术改造,能有效降低开发成本和周期及运维成本。该研究是区块链技术在水资源监管领域的初步探索,可为提升水资源管理能力提供新的技术思路与方案。

HLF区块链交易时延动态优化方法研究

Hyperledger Fabric(HLF)性能优化是区块链研究的热点问题,但当前工作对低负载生产环境中的交易时延关注不足,成为影响联盟链落地应用的重要因素。针对这一问题,提出了面向HLF的交易时延动态自适应优化方法:综合考虑交易到达率与交易大小维度,对HLF(v2.2)进行全面的性能评估,并给出了一组静态推荐配置参数;基于性能评估数据,使用XGBoost建立HLF性能模型,获得应用负载、网络配置、交易时延间的映射关系;对非饱和动态负载与突发注入攻击等场景进行模拟,获得贴近生产环境的应用负载输入;基于贝叶斯优化算法,对HLF进行动态自适应配置参数优化,有效降低HLF交易处理时延。通过实验,验证了优化方法的有效性,在多组随机动态负载输入中取得了平均53%、最高97%的交易时延优化效果。

基于区块链的水产交易计量数据采集与传输研究

为解决目前水产交易中手动录入计量数据易篡改、易丢失的问题,本研究提出一种基于区块链技术的水产交易计量数据采集与传输安全模型。首先设计一套基于树莓派的数据采集平台,用于数据的自动采集和录入;其次通过智能合约和共识机制保证所采集交易数据的传输与存储安全;最后,基于区块链技术设计一套水产交易计量数据采集与传输系统,实现水产交易计量数据采集和查询等功能,并基于Hyperledger Fabric平台搭建测试环境进行验证。结果显示,基于区块链技术的数据采集与传输系统可以有效地完成数据采集,保证数据传输与存储过程中的数据安全,数据传输率可达100%,丢包率相比传统传输系统更低。结果表明,本研究所提出的模型有效提高了数据的安全可靠性,提升了水产交易效率,更适合在实际水产交易中使用。

Preparation of MXene-based hybrids and their application in neuromorphic devices

The traditional von Neumann computing architecture has relatively-low information processing speed and high power consumption,making it difficult to meet the computing needs of artificial intelligence(AI).Neuromorphic computing systems,with massively parallel computing capability and low power consumption,have been considered as an ideal option for data storage and AI computing in the future.Memristor,as the fourth basic electronic component besides resistance,capacitance and inductance,is one of the most competitive candidates for neuromorphic computing systems benefiting from the simple structure,continuously adjustable conductivity state,ultra-low power consumption,high switching speed and compatibility with existing CMOS technology.The memristors with applying MXene-based hybrids have attracted significant attention in recent years.Here,we introduce the latest progress in the synthesis of MXene-based hybrids and summarize their potential applications in memristor devices and neuromorphological intelligence.We explore the development trend of memristors constructed by combining MXenes with other functional materials and emphatically discuss the potential mechanism of MXenes-based memristor devices.Finally,the future prospects and directions of MXene-based memristors are briefly described.

Two-photon polymerization-based 4D printing and its applications

Two-photon polymerization(TPP)is a cutting-edge micro/nanoscale three-dimensional(3D)printing technology based on the principle of two-photon absorption.TPP surpasses the diffraction limit in achieving feature sizes and excels in fabricating intricate 3D micro/nanostructures with exceptional resolution.The concept of 4D entails the fabrication of structures utilizing smart materials capable of undergoing shape,property,or functional changes in response to external stimuli over time.The integration of TPP and 4D printing introduces the possibility of producing responsive structures with micro/nanoscale accuracy,thereby enhancing the capabilities and potential applications of both technologies.This paper comprehensively reviews TPP-based 4D printing technology and its diverse applications.First,the working principles of TPP and its recent advancements are introduced.Second,the optional4D printing materials suitable for fabrication with TPP are discussed.Finally,this review paper highlights several noteworthy applications of TPP-based 4D printing,including domains such as biomedical microrobots,bioinspired microactuators,autonomous mobile microrobots,transformable devices and robots,as well as anti-counterfeiting microdevices.In conclusion,this paper provides valuable insights into the current status and future prospects of TPP-based4D printing technology,thereby serving as a guide for researchers and practitioners.

多功能热电织物用于可穿戴无线传感系统

Flexible thermoelectric materials play an important role in smart wearables,such as wearable power generation,self-powered sensing,and personal thermal management.However,with the rapid development of Internet of Things(IoT)and artificial intelligence(AI),higher standards for comfort,multifunctionality,and sustainable operation of wearable electronics have been proposed,and it remains challenging to meet all the requirements of currently reported thermoelectric devices.Herein,we present a multifunctional,wearable,and wireless sensing system based on a thermoelectric knitted fabric with over 600 mm·s^(-1)air permeability and a stretchability of 120%.The device coupled with a wireless transmission system realizes self-powered monitoring of human respiration through an mobile phone application(APP).Furthermore,an integrated thermoelectric system was designed to combine photothermal conversion and passive radiative cooling,enabling the characteristics of being powered by solar-driven in-plane temperature differences and monitoring outdoor sunlight intensity through the APP.Additionally,we decoupled the complex signals of resistance and thermal voltage during deformation under solar irradiation based on the anisotropy of the knitted fabrics to enable the device to monitor and optimize the outdoor physical activity of the athlete via the APP.This novel thermoelectric fabricbased wearable and wireless sensing platform has promising applications in next-generation smart textiles.

A Blockchain-Based Access Control Scheme for Reputation Value Attributes of the Internet of Things

The Internet of Things(IoT)access controlmechanism may encounter security issues such as single point of failure and data tampering.To address these issues,a blockchain-based IoT reputation value attribute access control scheme is proposed.Firstly,writing the reputation value as an attribute into the access control policy,and then deploying the access control policy in the smart contract of the blockchain system can enable the system to provide more fine-grained access control;Secondly,storing a large amount of resources fromthe Internet of Things in Inter Planetary File System(IPFS)to improve system throughput;Finally,map resource access operations to qualification tokens to improve the performance of the access control system.Complete simulation experiments based on the Hyperledger Fabric platform.Fromthe simulation experimental results,it can be seen that the access control system can achieve more fine-grained and dynamic access control while maintaining high throughput and low time delay,providing sufficient reliability and security for access control of IoT devices.

2D multifunctional devices:from material preparation to device fabrication and neuromorphic applications

Neuromorphic computing systems,which mimic the operation of neurons and synapses in the human brain,are seen as an appealing next-generation computing method due to their strong and efficient computing abilities.Two-dimensional (2D) materials with dangling bond-free surfaces and atomic-level thicknesses have emerged as promising candidates for neuromorphic computing hardware.As a result,2D neuromorphic devices may provide an ideal platform for developing multifunctional neuromorphic applications.Here,we review the recent neuromorphic devices based on 2D material and their multifunctional applications.The synthesis and next micro–nano fabrication methods of 2D materials and their heterostructures are first introduced.The recent advances of neuromorphic 2D devices are discussed in detail using different operating principles.More importantly,we present a review of emerging multifunctional neuromorphic applications,including neuromorphic visual,auditory,tactile,and nociceptive systems based on 2D devices.In the end,we discuss the problems and methods for 2D neuromorphic device developments in the future.This paper will give insights into designing 2D neuromorphic devices and applying them to the future neuromorphic systems.

Droplet morphology analysis of drop-on-demand inkjet printing

As an accurate 2D/3D fabrication tool,inkjet printing technology has great potential in preparation of micro electronic devices.The morphology of droplets produced by the inkjet printer has a great impact on the accuracy of deposition.In this study,the drop-on-demand(DoD)inkjet simulation model was established,and the accuracy of the simulation model was verified by corresponding experiments.The simulation result shows that the velocity of the droplet front and tail,as well as the time to disconnect from the nozzle is mainly affected by density(ρ),viscosity(μ)and surface tension(σ)of droplets.When the liquid filament is about to disconnect from the nozzle,the filament length and filament front velocity are found to have a linear correlation withσ/ρμand ln(ρ/(μσ1/2)).

Robust and Trustworthy Data Sharing Framework Leveraging On-Chain and Off-Chain Collaboration

The proliferation of Internet of Things(IoT)systems has resulted in the generation of substantial data,presenting new challenges in reliable storage and trustworthy sharing.Conventional distributed storage systems are hindered by centralized management and lack traceability,while blockchain systems are limited by low capacity and high latency.To address these challenges,the present study investigates the reliable storage and trustworthy sharing of IoT data,and presents a novel system architecture that integrates on-chain and off-chain data manage systems.This architecture,integrating blockchain and distributed storage technologies,provides high-capacity,high-performance,traceable,and verifiable data storage and access.The on-chain system,built on Hyperledger Fabric,manages metadata,verification data,and permission information of the raw data.The off-chain system,implemented using IPFS Cluster,ensures the reliable storage and efficient access to massive files.A collaborative storage server is designed to integrate on-chain and off-chain operation interfaces,facilitating comprehensive data operations.We provide a unified access interface for user-friendly system interaction.Extensive testing validates the system’s reliability and stable performance.The proposed approach significantly enhances storage capacity compared to standalone blockchain systems.Rigorous reliability tests consistently yield positive outcomes.With average upload and download throughputs of roughly 20 and 30 MB/s,respectively,the system’s throughput surpasses the blockchain system by a factor of 4 to 18.

一种基于区块链的票据可信管理方案

在传统票据市场中,以电子商业汇票系统为核心的集中管理模式导致信息不对称、人工操作失误、监督溯源效率低等问题频发,因此,票据交易的真实性、安全性存疑。针对以上问题,该文利用区块链技术去中心化、不可篡改、可溯源的特性,提出了一种基于区块链的票据交易可信管理方案。通过设计去中心化的数据结构和验证机制,实现了交易合同的去中心化可信存储,确保了交易背景的真实性;并采用去中心化的验证方式建立了票据交易真实性和完整性验证机制,实现了交易数据的可信验证;此外,通过结合区块链技术和可信执行环境,建立节点身份远程验证机制,实现了节点身份信息的去中心化真实性验证,确保了参与方身份真实性。最后,采用Hyperledger Fabric区块链平台对方案进行了仿真实现和测试,结果表明,该方案实现了票据交易合同和签发的可信管理。

Engineering graphene oxide and hydrogel coatings on fabrics for smart Janus textiles with superior thermal regulation

Fabric multifunctionality offers resource savings and enhanced human comfort.This study innovatively integrates cooling,heating,and antimicrobial properties within a Janus fabric,surpassing previous research focused solely on cooling or heating.Different effects are achieved by applying distinct coatings to each side of the fabric.One graphene oxide(GO)coating exhibits exceptional light-to-heat conversion,absorbing and transforming light energy into heat,thereby elevating fabric temperature by 15.4℃,22.7℃,and 43.7℃ under 0.2,0.5,and 1 sun irradiation,respectively.Conversely,a hydrogel coating on one side absorbs water,facilitating heat dissipation through evaporation upon light exposure,reducing fabric temperature by 5.9℃,8.4℃,and 7.1℃ in 0.2,0.5,and 1 sun irradiation,respectively.Moreover,both sides of Janus fabric exhibit potent antimicrobial properties,ensuring fabric hygiene.This work presents a feasible solution to address crucial challenges in fabric thermal regulation,providing a smart approach for intelligent adjustment of body comfort in both summer and winter.By integrating heating and cooling capabilities along with antimicrobial properties,this study promotes sustainable development in textile techniques.

Robust,Flexible,and Superhydrophobic Fabrics for High-Efficiency and Ultrawide-Band Microwave Absorption

Microwave absorption(MA)materials are essential for protecting against harmful electromagnetic radiation.In this study,highly efficient and ultrawide-band microwave-absorbing fabrics with superhydrophobic surface features were developed using a facile dip-coating method involving in situ graphene oxide(GO)reduction,deposition of TiO_(2) nanoparticles,and subsequent coating of a mixture of polydimethylsiloxane(PDMS)and octadecylamine(ODA)on polyester fabrics.Owing to the presence of hierarchically structured surfaces and low-surface-energy materials,the resultant reduced GO(rGO)/TiO_(2)-ODA/PDMS-coated fabrics demonstrate superhydrophobicity with a water contact angle of 159°and sliding angle of 5°.Under the synergistic effects of conduction loss,interface polarization loss,and surface roughness topography,the optimized fabrics show excellent microwave absorbing performances with a minimum reflection loss(RL_(min))of47.4 dB and a maximum effective absorption bandwidth(EAB_(max))of 7.7 GHz at a small rGO loading of 6.9 wt%.In addition,the rGO/TiO_(2)-ODA/PDMS coating was robust,and the coated fabrics could withstand repeated washing,soiling,long-term ultraviolet irradiation,and chemical attacks without losing their superhydrophobicity and MA properties.Moreover,the coating imparts self-healing properties to the fabrics.This study provides a promising and effective route for the development of robust and flexible materials with microwave-absorbing properties.

Atomically self-healing of structural defects in monolayer WSe_(2)

Minimizing disorder and defects is crucial for realizing the full potential of two-dimensional transition metal dichalcogenides(TMDs) materials and improving device performance to desired properties. However, the methods in defect controlcurrently face challenges with overly large operational areas and a lack of precision in targeting specific defects. Therefore,we propose a new method for the precise and universal defect healing of TMD materials, integrating real-time imaging withscanning transmission electron microscopy (STEM). This method employs electron beam irradiation to stimulate the diffusionmigration of surface-adsorbed adatoms on TMD materials grown by low-temperature molecular beam epitaxy (MBE),and heal defects within the diffusion range. This approach covers defect repairs ranging from zero-dimensional vacancydefects to two-dimensional grain orientation alignment, demonstrating its universality in terms of the types of samples anddefects. These findings offer insights into the use of atomic-level focused electron beams at appropriate voltages in STEMfor defect healing, providing valuable experience for achieving atomic-level precise fabrication of TMD materials.

Holistic and localized preparation methods for triboelectric sensors:principles,applications and perspectives

With the arrival of intelligent terminals,triboelectric nanogenerators,as a new kind of energy converter,are considered one of the most important technologies for the next generation of intelligent electronics.As a self-powered sensor,it can greatly reduce the power consumption of the entire sensing system by transforming external mechanical energy to electricity.However,the fabrication method of triboelectric sensors largely determines their functionality and performance.This review provides an overview of various methods used to fabricate triboelectric sensors,with a focus on the processes of micro-electro-mechanical systems technology,three-dimensional printing,textile methods,template-assisted methods,and material synthesis methods for manufacturing.The working mechanisms and suitable application scenarios of various methods are outlined.Subsequently,the advantages and disadvantages of various methods are summarized,and reference schemes for the subsequent application of these methods are included.Finally,the opportunities and challenges faced by different methods are discussed,as well as their potential for application in various intelligent systems in the Internet of Things.