86 research outputs found

    Jacquard-woven photonic bandgap fiber displays

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    We present an overview of photonic textile displays woven on a Jacquard loom, using newly discovered polymer photonic bandgap fibers that have the ability to change color and appearance when illuminated with ambient or transmitted light. The photonic fiber can be thin (smaller than 300 microns in diameter) and highly flexible, which makes it possible to weave in the weft on a computerized Jacquard loom and develop intricate double weave structures together with a secondary weft yarn. We demonstrate how photonic crystal fibers enable a variety of color and structural patterns on the textile, and how dynamic imagery can be created by balancing the ambient and emitted radiation. Finally, a possible application in security ware for low visibility conditions is described as an example

    An Energy-Autonomous Smart Shirt employing wearable sensors for Usersโ€™ Safety and Protection in Hazardous Workplaces

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    none4siWearable devices represent a versatile technology in the IoT paradigm, enabling noninvasive and accurate data collection directly from the human body. This paper describes the development of a smart shirt to monitor working conditions in particularly dangerous workplaces. The wearable device integrates a wide set of sensors to locally acquire the userโ€™s vital signs (e.g., heart rate, blood oxygenation, and temperature) and environmental parameters (e.g., the concentration of dangerous gas species and oxygen level). Electrochemical gas-monitoring modules were designed and integrated into the garment for acquiring the concentrations of CO, O2, CH2O, and H2S. The acquired data are wirelessly sent to a cloud platform (IBM Cloud), where they are displayed, processed, and stored. A mobile application was deployed to gather data from the wearable devices and forward them toward the cloud application, enabling the system to operate in areas where aWiFi hotspot is not available. Additionally, the smart shirt comprises a multisource harvesting section to scavenge energy from light, body heat, and limb movements. Indeed, the wearable device integrates several harvesters (thin-film solar panels, thermoelectric generators (TEGs), and piezoelectric transducers), a low-power conditioning section, and a 380 mAh LiPo battery to accumulate the recovered charge. Field tests indicated that the harvesting section could provide up to 216 mW mean power, fully covering the power requirements (P = 1.86 mW) of the sensing, processing, and communication sections in all considered conditions (3.54 mW in the worst-case scenario). However, the 380 mAh LiPo battery guarantees about a 16-day lifetime in the complete absence of energy contributions from the harvesting section.Special Issue โ€œInnovative Materials, Smart Sensors and IoT-based Electronic Solutions for Wearable Applicationsโ€, https://www.mdpi.com/journal/applsci/special_issues/Materials_Sensors_Electronic_Solutions_Wearable_ApplicationsopenRoberto De Fazio, Abdel-Razzak Al-Hinnawi, Massimo De Vittorio, Paolo ViscontiDE FAZIO, Roberto; Al-Hinnawi, Abdel-Razzak; DE VITTORIO, Massimo; Visconti, Paol

    The 2021 flexible and printed electronics roadmap

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    This roadmap includes the perspectives and visions of leading researchers in the key areas of flexible and printable electronics. The covered topics are broadly organized by the device technologies (sections 1โ€“9), fabrication techniques (sections 10โ€“12), and design and modeling approaches (sections 13 and 14) essential to the future development of new applications leveraging flexible electronics (FE). The interdisciplinary nature of this field involves everything from fundamental scientific discoveries to engineering challenges; from design and synthesis of new materials via novel device design to modelling and digital manufacturing of integrated systems. As such, this roadmap aims to serve as a resource on the current status and future challenges in the areas covered by the roadmap and to highlight the breadth and wide-ranging opportunities made available by FE technologies

    Trends of biosensing: plasmonics through miniaturization and quantum sensing

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    Despite being extremely old concepts, plasmonics and surface plasmon resonance-based biosensors have been increasingly popular in the recent two decades due to the growing interest in nanooptics and are now of relevant significance in regards to applications associated with human health. Plasmonics integration into point-of-care devices for health surveillance has enabled significant levels of sensitivity and limit of detection to be achieved and has encouraged the expansion of the fields of study and market niches devoted to the creation of quick and incredibly sensitive label-free detection. The trend reflects in wearable plasmonic sensor development as well as point-of-care applications for widespread applications, demonstrating the potential impact of the new generation of plasmonic biosensors on human well-being through the concepts of personalized medicine and global health. In this context, the aim here is to discuss the potential, limitations, and opportunities for improvement that have arisen as a result of the integration of plasmonics into microsystems and lab-on-chip over the past five years. Recent applications of plasmonic biosensors in microsystems and sensor performance are analyzed. The final analysis focuses on the integration of microfluidics and lab-on-a-chip with quantum plasmonics technology prospecting it as a promising solution for chemical and biological sensing. Here it is underlined how the research in the field of quantum plasmonic sensing for biological applications has flourished over the past decade with the aim to overcome the limits given by quantum fluctuations and noise. The significant advances in nanophotonics, plasmonics and microsystems used to create increasingly effective biosensors would continue to benefit this field if harnessed properly

    Implementation of Low-Cost and Open-Source Instrumentation in 2D Material Research

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    This dissertation examines the importance of open-sourced scientific instrumentation in two-dimensional (2D) material research. 2D materials are gaining attention due to their extraordinary electrical, mechanical, optical, and thermal properties and their potential to transform various fields. However, studying these materials often requires complex and expensive scientific instrumentation, which can limit the accessibility and progress of research. The study explores the potential of open-source software and hardware in scientific instrumentation, and its role in democratizing access, fostering collaboration, and accelerating innovation. The study presents two instruments implemented for 2D material research, using only open-source software and hardware, and demonstrates experiments conducted with these instruments. Additionally, the study explores broader implications of open-sourced scientific instrumentation by demonstrating a motorized variable filter stage and retractable leadless pacemaker. The dissertation concludes by emphasizing the critical role of open-source instruments in the advancement of material science and the broader scientific community and the need for ongoing support and engagement to fully realize their potential

    IoT and Sensor Networks in Industry and Society

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    The exponential progress of Information and Communication Technology (ICT) is one of the main elements that fueled the acceleration of the globalization pace. Internet of Things (IoT), Artificial Intelligence (AI) and big data analytics are some of the key players of the digital transformation that is affecting every aspect of human's daily life, from environmental monitoring to healthcare systems, from production processes to social interactions. In less than 20 years, people's everyday life has been revolutionized, and concepts such as Smart Home, Smart Grid and Smart City have become familiar also to non-technical users. The integration of embedded systems, ubiquitous Internet access, and Machine-to-Machine (M2M) communications have paved the way for paradigms such as IoT and Cyber Physical Systems (CPS) to be also introduced in high-requirement environments such as those related to industrial processes, under the forms of Industrial Internet of Things (IIoT or I2oT) and Cyber-Physical Production Systems (CPPS). As a consequence, in 2011 the German High-Tech Strategy 2020 Action Plan for Germany first envisioned the concept of Industry 4.0, which is rapidly reshaping traditional industrial processes. The term refers to the promise to be the fourth industrial revolution. Indeed, the ๏ฌrst industrial revolution was triggered by water and steam power. Electricity and assembly lines enabled mass production in the second industrial revolution. In the third industrial revolution, the introduction of control automation and Programmable Logic Controllers (PLCs) gave a boost to factory production. As opposed to the previous revolutions, Industry 4.0 takes advantage of Internet access, M2M communications, and deep learning not only to improve production efficiency but also to enable the so-called mass customization, i.e. the mass production of personalized products by means of modularized product design and ๏ฌ‚exible processes. Less than five years later, in January 2016, the Japanese 5th Science and Technology Basic Plan took a further step by introducing the concept of Super Smart Society or Society 5.0. According to this vision, in the upcoming future, scientific and technological innovation will guide our society into the next social revolution after the hunter-gatherer, agrarian, industrial, and information eras, which respectively represented the previous social revolutions. Society 5.0 is a human-centered society that fosters the simultaneous achievement of economic, environmental and social objectives, to ensure a high quality of life to all citizens. This information-enabled revolution aims to tackle todayโ€™s major challenges such as an ageing population, social inequalities, depopulation and constraints related to energy and the environment. Accordingly, the citizens will be experiencing impressive transformations into every aspect of their daily lives. This book offers an insight into the key technologies that are going to shape the future of industry and society. It is subdivided into five parts: the I Part presents a horizontal view of the main enabling technologies, whereas the II-V Parts offer a vertical perspective on four different environments. The I Part, dedicated to IoT and Sensor Network architectures, encompasses three Chapters. In Chapter 1, Peruzzi and Pozzebon analyse the literature on the subject of energy harvesting solutions for IoT monitoring systems and architectures based on Low-Power Wireless Area Networks (LPWAN). The Chapter does not limit the discussion to Long Range Wise Area Network (LoRaWAN), SigFox and Narrowband-IoT (NB-IoT) communication protocols, but it also includes other relevant solutions such as DASH7 and Long Term Evolution MAchine Type Communication (LTE-M). In Chapter 2, Hussein et al. discuss the development of an Internet of Things message protocol that supports multi-topic messaging. The Chapter further presents the implementation of a platform, which integrates the proposed communication protocol, based on Real Time Operating System. In Chapter 3, Li et al. investigate the heterogeneous task scheduling problem for data-intensive scenarios, to reduce the global task execution time, and consequently reducing data centers' energy consumption. The proposed approach aims to maximize the efficiency by comparing the cost between remote task execution and data migration. The II Part is dedicated to Industry 4.0, and includes two Chapters. In Chapter 4, Grecuccio et al. propose a solution to integrate IoT devices by leveraging a blockchain-enabled gateway based on Ethereum, so that they do not need to rely on centralized intermediaries and third-party services. As it is better explained in the paper, where the performance is evaluated in a food-chain traceability application, this solution is particularly beneficial in Industry 4.0 domains. Chapter 5, by De Fazio et al., addresses the issue of safety in workplaces by presenting a smart garment that integrates several low-power sensors to monitor environmental and biophysical parameters. This enables the detection of dangerous situations, so as to prevent or at least reduce the consequences of workers accidents. The III Part is made of two Chapters based on the topic of Smart Buildings. In Chapter 6, Petroศ™anu et al. review the literature about recent developments in the smart building sector, related to the use of supervised and unsupervised machine learning models of sensory data. The Chapter poses particular attention on enhanced sensing, energy efficiency, and optimal building management. In Chapter 7, Oh examines how much the education of prosumers about their energy consumption habits affects power consumption reduction and encourages energy conservation, sustainable living, and behavioral change, in residential environments. In this Chapter, energy consumption monitoring is made possible thanks to the use of smart plugs. Smart Transport is the subject of the IV Part, including three Chapters. In Chapter 8, Roveri et al. propose an approach that leverages the small world theory to control swarms of vehicles connected through Vehicle-to-Vehicle (V2V) communication protocols. Indeed, considering a queue dominated by short-range car-following dynamics, the Chapter demonstrates that safety and security are increased by the introduction of a few selected random long-range communications. In Chapter 9, Nitti et al. present a real time system to observe and analyze public transport passengers' mobility by tracking them throughout their journey on public transport vehicles. The system is based on the detection of the active Wi-Fi interfaces, through the analysis of Wi-Fi probe requests. In Chapter 10, Miler et al. discuss the development of a tool for the analysis and comparison of efficiency indicated by the integrated IT systems in the operational activities undertaken by Road Transport Enterprises (RTEs). The authors of this Chapter further provide a holistic evaluation of efficiency of telematics systems in RTE operational management. The book ends with the two Chapters of the V Part on Smart Environmental Monitoring. In Chapter 11, He et al. propose a Sea Surface Temperature Prediction (SSTP) model based on time-series similarity measure, multiple pattern learning and parameter optimization. In this strategy, the optimal parameters are determined by means of an improved Particle Swarm Optimization method. In Chapter 12, Tsipis et al. present a low-cost, WSN-based IoT system that seamlessly embeds a three-layered cloud/fog computing architecture, suitable for facilitating smart agricultural applications, especially those related to wildfire monitoring. We wish to thank all the authors that contributed to this book for their efforts. We express our gratitude to all reviewers for the volunteering support and precious feedback during the review process. We hope that this book provides valuable information and spurs meaningful discussion among researchers, engineers, businesspeople, and other experts about the role of new technologies into industry and society

    ์ „์ž์†Œ์ž๋กœ ์‘์šฉ์„ ์œ„ํ•œ ์ „์ด๊ธˆ์†๊ณ„ํ™”ํ•ฉ๋ฌผ์˜ ์ง์ ‘ ํ•ฉ์„ฑ์— ๊ด€ํ•œ ์—ฐ๊ตฌ

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    ํ•™์œ„๋…ผ๋ฌธ(๋ฐ•์‚ฌ) -- ์„œ์šธ๋Œ€ํ•™๊ต๋Œ€ํ•™์› : ์ž์—ฐ๊ณผํ•™๋Œ€ํ•™ ํ™”ํ•™๋ถ€, 2021.8. ํ™๋ณ‘ํฌ.์ „์ด๊ธˆ์†๊ณ„ํ™”ํ•ฉ๋ฌผ์€ ๋›ฐ์–ด๋‚œ ๊ธฐ๊ณ„์ , ๊ด‘ํ•™์ , ์ „๊ธฐ์  ํŠน์„ฑ์œผ๋กœ ์ธํ•ด ์ฐจ์„ธ๋Œ€ ์ƒ์—…์šฉ ํ”Œ๋ ‰์‹œ๋ธ” ๋กœ์ง ๋””๋ฐ”์ด์Šค ๋ฐ ์„ผ์„œ๋ฅผ ๊ฐœ๋ฐœํ•˜๊ธฐ์œ„ํ•œ ํƒ์›”ํ•œ ํ”Œ๋žซํผ์œผ๋กœ ์ž…์„ ์ˆ˜ ์žˆ๋Š” ์ „์ž๊ธฐ๊ธฐ ์ œ์ž‘์„ ์œ„ํ•œ ํผ ํŒฉํ„ฐ๋ฅผ ๋ถ€์—ฌํ•  ์ˆ˜ ์žˆ์Šต๋‹ˆ๋‹ค. ์ด๋ฅผ ๊ตฌํ˜„ํ•˜๊ธฐ ์œ„ํ•ด ์ „์ด๊ธˆ์†๊ณ„ํ™”ํ•ฉ๋ฌผ์˜ ๋Œ€๋ฉด์  ๋ฐ•๋ง‰ ํ•ฉ์„ฑ๋ฒ•์€ ๋ณต์žกํ•œ ์ง„๊ณต ๊ธฐ๋ฐ˜ ์ ‘๊ทผ ๋ฐฉ์‹์„ ๊ฑฐ์น˜๋Š” ๋ฌธ์ œ์ ์„ ์ง€๋…€์™”์Šต๋‹ˆ๋‹ค. ๋”ฐ๋ผ์„œ, ์ž„์˜์˜ ๊ธฐํŒ ์œ„์— ๋Œ€๋ฉด์  ์ „์ด๊ธˆ์†๊ณ„ํ™”ํ•ฉ๋ฌผ ๋ฐ•๋ง‰์„ ํ•ฉ์„ฑํ•˜์—ฌ ๋Œ€๋Ÿ‰ ์ƒ์‚ฐ์„ ์ง„ํ–‰ํ•  ์ˆ˜ ์žˆ๋Š” ๊ฐ„๋‹จํ•˜๊ณ  ํšจ๊ณผ์ ์ธ ๋ฐฉ๋ฒ•์„ ๊ฐœ๋ฐœํ•˜๋Š” ๊ฒƒ์ด ์ค‘์š”ํ•ฉ๋‹ˆ๋‹ค. ์ด ์ ์—์„œ ์šฉ์•ก ๊ธฐ๋ฐ˜ ์ „์ด๊ธˆ์†๊ณ„ํ™”ํ•ฉ๋ฌผ ํ•ฉ์„ฑ ๋ฐฉ๋ฒ•์€ ๋น„ ์ง„๊ณต ๋ถ„์œ„๊ธฐ์—์„œ ์ œ์กฐ ๊ณต์ •์˜ ๋‹จ์ˆœํ™”์™€ ๋Œ€๋ฉด์ ํ™”๋ฅผ ๋™์‹œ์— ์ด๋ฃฐ ์ˆ˜ ์žˆ๋Š” ํšจ์œจ์ ์ธ ํ•ฉ์„ฑ๋ฒ•์ž…๋‹ˆ๋‹ค. ์ œ1์žฅ์—์„œ๋Š” ์šฉ์•ก๊ณต์ • ๊ธฐ๋ฐ˜์˜ ์ „์ด๊ธˆ์†๊ณ„ํ™”ํ•ฉ๋ฌผ ์ „๊ตฌ์ฒด ๋ฐ•๋ง‰ ์ฆ์ฐฉ ๋ฐ ํ•ฉ์„ฑ์˜ ๋ฐœ์ „ ๊ณผ์ •์„ ์š”์•ฝํ•˜๊ณ , ์ฆ์ฐฉ ๋œ ์ „๊ตฌ์ฒด๋ฅผ ์—ด๋ถ„ํ•ด ์‹œ์ผœ์„œ ์ „์ด๊ธˆ์†๊ณ„ํ™”ํ•ฉ๋ฌผ ๋ฐ•๋ง‰์œผ๋กœ ํ˜•์„ฑํ•˜๋Š” ํ•ฉ์„ฑ ๋ฐฉ๋ฒ•์˜ ์žฅ๋‹จ์ ์— ๋Œ€ํ•ด ๋…ผ์˜ํ•ฉ๋‹ˆ๋‹ค. ๋งˆ์ง€๋ง‰์œผ๋กœ๋Š” ์ „์ž๊ธฐ๊ธฐ ๋ฐ ์„ผ์„œ์—์„œ ๋ฏธ๋ž˜์— ์ ์šฉ ๊ฐ€๋Šฅํ•œ ์‘์šฉ๋ถ„์•ผ์— ๋Œ€ํ•ด ์„ค๋ช…ํ•ฉ๋‹ˆ๋‹ค. ์ œ2์žฅ์—์„œ๋Š” ๋น„์ง„๊ณต ์ƒํƒœ์—์„œ ํŽ„์Šค ๋ ˆ์ด์ € ์–ด๋‹๋ง ๊ธฐ๋ฒ• (ฮป = 1.06 ฮผm, ํŽ„์Šค ์ง€์† ์‹œ๊ฐ„ ~ 100 ps)์„ ์‚ฌ์šฉํ•˜์—ฌ ์›จ์ดํผ ๊ทœ๋ชจ์—์„œ ์ดํ™ฉํ™”๋ชฐ๋ฆฌ๋ธŒ๋ฐ๋„˜ ๋ฐ ์ดํ™ฉํ™”ํ……์Šคํ… ๊ตฌ์กฐ์˜ ์ธต๊ฐ„ ์„ ํƒ ํ•ฉ์„ฑ์„ ์œ„ํ•œ ์ง์ ‘์ ์ด๊ณ  ์‹ ์†ํ•œ ์ œ์ž‘ ๋ฐฉ๋ฒ•์„ ์†Œ๊ฐœํ•ฉ๋‹ˆ๋‹ค. ๊ทธ ๊ฒฐ๊ณผ ์ดํ™ฉํ™”๋ชฐ๋ฆฌ๋ธŒ๋ฐ๋„˜ ๊ธฐ๋ฐ˜ ์ „๊ณ„ ํšจ๊ณผ ํŠธ๋žœ์ง€์Šคํ„ฐ, ํ”ผ๋ถ€ ๋ถ€์ฐฉ ํ˜• ๋ชจ์…˜ ์„ผ์„œ ๋ฐ ์ดํ™ฉํ™”๋ชฐ๋ฆฌ๋ธŒ๋ฐ๋„˜/์ดํ™ฉํ™”ํ……์Šคํ… ๊ธฐ๋ฐ˜ ์ด์ข… ์ ‘ํ•ฉ ๋‹ค์ด์˜ค๋“œ์˜ ๋™์ž‘์„ ์‹œ์—ฐํ–ˆ์Šต๋‹ˆ๋‹ค. ์ œ3 ์žฅ์—์„œ๋Š” ํ‘œ๋ฉด์ด ๊ตฌ๊ฒจ์ง„ ํ˜•ํƒœ๋ฅผ ๊ฐ€์ง€๋Š” ์ดํ™ฉํ™”๋ชฐ๋ฆฌ๋ธŒ๋ฐ๋„˜ ๊ธฐ๋ฐ˜ ๋งˆ์ฐฐ ์ „๊ธฐ ๋ฐœ์ƒ ์žฅ์น˜๋ฅผ ์ œ์ž‘ํ•˜์—ฌ ๊ธฐ์กด์˜ ์ดํ™ฉํ™” ๋ชฐ๋ฆฌ๋ธŒ๋ฐ๋„˜ ๋Œ€๋น„ ์•ฝ 40 % ํ–ฅ์ƒ๋œ ์ „๋ ฅ์„ ๊ฐ€์ง€๋Š” ์ดํ™ฉํ™”๋ชฐ๋ฆฌ๋ธŒ๋ฐ๋„˜์˜ ํ˜•ํƒœํ•™์  ๊ตฌ์กฐ๋ฅผ ์†์‰ฝ๊ฒŒ ์กฐ์ ˆํ•˜๋Š” ํ•ฉ์„ฑ๋ฒ•์„ ์†Œ๊ฐœํ•ฉ๋‹ˆ๋‹ค. ํ‘œ๋ฉด์ด ๊ตฌ๊ฒจ์ง„ ํ˜•ํƒœ์˜ ์ดํ™ฉํ™”๋ชฐ๋ฆฌ๋ธŒ๋ฐ๋„˜ ๊ธฐ๋ฐ˜ ๋งˆ์ฐฐ ์ „๊ธฐ ๋ฐœ์ƒ ์žฅ์น˜๋Š” ์ถ”๊ฐ€ ๊ณต์ • ๋ฐ ์žฌ๋ฃŒ์˜ ๋„์›€์—†์ด ๊ณ ์„ฑ๋Šฅ ์—๋„ˆ์ง€ ์ˆ˜ํ™• ํšจ์œจ์„ ์ตœ๋Œ€ ~ 25V ๋ฐ ~ 1.2 ฮผA ๊นŒ์ง€ ๋ณด์—ฌ์ค๋‹ˆ๋‹ค. ๋งˆ์ง€๋ง‰์œผ๋กœ, 4์žฅ์—์„œ๋Š” ์œ„ ์‹คํ—˜๋“ค์— ๊ด€ํ•œ ๊ฒฐ๋ก ์„ ๊ธฐ์ˆ  ํ•˜๋Š” ๊ฒƒ์œผ๋กœ ์ด ๋…ผ๋ฌธ์„ ๋งˆ๋ฌด๋ฆฌํ•˜์˜€๋‹ค.Transition metal dichalcogenides (TMDC) have been identified as excellent platforms for developing the next-generation commercial flexible logic devices and sensors, owing to their outstanding mechanical, optical, and electrical properties. The TMDCs can be used to produce novel form-factors for wearable electronic devices. Typically, synthesis of large-scale TMDC thin film have been achieved by complexity vacuum-based approach. Therefore, it is essential to develop a simple and effective method to boost-up mass production of TMDC thin films on a large scale upon arbitrary substrates. In this regard, the solution-based TMDC synthesis method is advantageous because it proposes a simplification of the fabrication processes and an easy scaling-up of the material with a non-vacuum system. In Chapter 1, we summarize the evolution of the solution-based thin-film preparation and synthesis of the TMDCs; subsequently, we discuss the merits and drawbacks of the recently developed methods to form TMDC thin films directly from the deposited precursor. Finally, we discuss the practical applications of the TMDC thin films, which demonstrate the feasibility of their commercialized applications in electronic devices and sensors. In Chapter 2, we introduce a direct and rapid method for layer-selective synthesis of MoS2 and WS2 structures in wafer-scale using a pulsed laser annealing system (ฮป = 1.06 ฮผm, pulse duration โˆผ100 ps) in ambient conditions. As a proof of concept, we demonstrated the behavior of a MoS2-based field-effect transistor, a skin-attachable motion sensor, and a MoS2/WS2-based heterojunction diode in this study. In Chapter 3, we demonstrate synthesis technique to adjusting MoS2 morphological structure, so that a surface-crumpled MoS2 TENG device generates ~40% more power than a flat MoS2 one. Compared to other MoS2-based TENG devices, it shows high-performance energy harvesting (up to ~25 V and ~1.2 ฮผA) without assistance from other materials, even when the counterpart triboelectric surface has a slightly different triboelectric series. In Chapter 4, the summary and conclusion of the thesis are depicted, finally.Chapter 1. Introducton of Large-Scale Synthesis of Transition Metal Dichalcogenide 1 1. 1. Introduction 1 1. 2. Synthesis of TMDC thin films by thermolysis 3 1. 2. 1. Principles of thermolysis 3 1. 2. 2. Characteristics 5 1. 2. 3. Synthesis of TMDC films on a large scale 8 1. 2. 4. Synthesis of direct-patterned TMDC films 12 1. 3. Applications of TMDCs 17 1. 3. 1. Field-effect transistors (FETs) 17 1. 3. 2. Photodetectors 18 1. 3. 3. Hydrogen evolution reactor (HER) 19 1. 3. 4. Strain and haptic sensors 22 1. 4. Perspectives and summary 25 1. 5. References 26 Chapter 2. Layer-Selective Synthesis of MoS2 and WS2 Structures under Ambient Conditions for Customized Electronics 30 2. 1. Abstract 30 2. 2. Introduction 31 2. 3. Expermental 34 2. 4. Results and discussion 36 2. 5. Conclusion 68 2. 6. References 69 Chapter 3. Laser-Directed Synthesis of Strain-Induced Crumpled MoS2 Structure for Enhanced Triboelectrification toward Haptic Sensors 73 3. 1. Abstract 73 3. 2. Introduction 74 3. 3. Expermental 77 3. 4. Results and discussion 80 3. 5. Conclusion 113 3. 6. References 114 Chapter 4. Conclusion 124 Abstract (in Korean) 126๋ฐ•

    New trends in 4D printing: A critical review

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    In a variety of industries, Additive Manufacturing has revolutionized the whole design-fabrication cycle. Traditional 3D printing is typically employed to produce static components, which are not able to fulfill the dynamic structures requirements and relevant applications such as soft grippers, self-assembly systems, and smart actuators. To address this limitation, an innovative technology has emerged and is called โ€œ4D printingโ€. It processes smart materials by using 3D printing for fabricating smart structures that can be reconfigured by applying different inputs such as heat, humidity, magnetic, electricity, light etc. At present, 4D printing is still a growing technology and it presents numerous challenges regarding materials, design, simulation, fabrication processes, applied strategies and reversibility. In this work a critical review about 4D printing technologies, materials and applications is discussed

    Development of soft modular robotics

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    This thesis covers the development and validation of soft robots in providing upper limb assistive motion. The main purpose of this research is to develop highly compliant and resilient actuators that generate motion for elbow and shoulder movements. To accomplish the purpose of the study, the fabrication, geometric construction along with experimental data of pressure, torque and range of motion of all developed actuators are described. The main contribution of this thesis is the development of soft actuators that transfer force via elastic deformation in order to generate assistive motion; features such as flexibility and soft contact with the skin ensure excellent safety potential of the actuators. To reduce the instability phenomenon attributed to the elastic response of rubber under large deformations that leads to bulging, the implementation of a pleated network design and embedded braided mesh network is presented. Bulging was reduced and torque output was increased with the integration of braided mesh into the silicone rubber actuator. The soft actuators developed for elbow and shoulder motion was tested on ten healthy participants thereby demonstrating its comfort, ease of use, fitting and removal as well as its practicality as an assistive apparatus for stroke patients. The use of soft robotics to provide shoulder motion was also assessed by the integration of soft robotics with a gravity compensated exoskeleton. The developed soft actuators were powered with electro-pneumatic hardware components presented in a compact, embedded form. Positive and negative air pressure control was implemented by a piecewise linear control algorithm with the performance of the controller shown. The design of a novel muscle made entirely of silicone rubber that contract upon actuation was described together with the manufacturing procedure, design parameters and measurement results of performance of these muscles such as the velocity of shortening, isometric contraction and maximal obtainable muscle force (without shortening). The muscles are manufactured to mimic the skeletal muscles present in the human body. These muscles are composed of a number of wedge-like units in series, the number of these wedge units increase the contraction. The soft muscles were characterized in order to find optimum design parameters that results in more contraction and speed; the muscles were tested on a model hinge joint to execute flexion/extension of the forearm at the elbow. Aside from contracting, the muscle has an interesting capability of producing bidirectional bending by the regulation of internal positive and negative air pressure in each wedge unit. In order to measure performance data relating to range of motion from bending, rotary and muscle actuators, computer vision processing was made use of. Soft robots are made with materials that experience large deformations, the sensors used to obtain measurement data can either be through the use of embedded sensors or visual processing. The use of embedded sensors can be cumbersome, resulting in limitation of its performance. The visual processing algorithms implemented to measure performance data such as angle of motion, bending angle and contraction ratio in real-time using a Webcam is described. Visual processing concepts such as colour tracking, template matching, camera calibration were applied. The developed vision system was applied to execute vision based motion control which is able to move the soft robot to a desired position using high level vision control and lower level pressure control. The material described in the preceding paragraphs are presented in an interrelated format. A concise introduction to the thesis is presented in the first chapter. An extensive survey of the field of soft robotics including materials, manufacturing procedure, actuation principles, primary accomplishments, control and challenges are presented in the literature review chapter, together with a review of rehabilitation devices. Since this work focused on the use of silicone rubber as actuator material, a brief introduction to working with silicone rubber as an engineering material is presented in the third chapter. The conclusions of the work and suggestions for future research are provided at the last chapter of this thesis
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