Flexible hydrogels are receiving significant attention for their application in wearable sensors.However,most hydrogel materials exhibit weak and one-time adhesion,low sensitivity,ice crystallization,water evaporation...Flexible hydrogels are receiving significant attention for their application in wearable sensors.However,most hydrogel materials exhibit weak and one-time adhesion,low sensitivity,ice crystallization,water evaporation,and poor self-recovery,thereby limiting their application as sensors.These issues are only partly addressed in previous studies.Herein,a multiplecrosslinked poly(2-(methacryloyloxy)ethyl)dimethyl-(3-sulfopropyl)ammonium hydroxide-co-acrylamide)(P(SBMA-co-AAm))multifunctional hydrogel is prepared via a one-pot synthesis method to overcome the aforementioned limitations.Specifically,ions,glycerol,and 2-(methacryloyloxy)ethyl)dimethyl-(3-sulfopropyl)ammonium hydroxide are incorporated to reduce the freezing point and improve the moisture retention ability.The proposed hydrogel is superior to existing hydrogels because it exhibits good stretchability(a strain of 2900%),self-healing properties,and transparency through effective energy dissipation in its dynamic crosslinked network.Further,2-(methacryloyloxy)ethyl)dimethyl-(3-sulfopropyl)ammonium hydroxide as a zwitterion monomer results in an excellent gauge factor of 43.4 at strains of 1300-1600%by improving the ion transportability and achieving a strong adhesion of 20.9 kPa owing to the dipole-dipole moment.The proposed hydrogel is promising for next-generation biomedical applications,such as soft robots,and health monitoring.展开更多
Recent years have witnessed a huge demand for ubiquitous communications services from continuously moving users. In order to provide seamless network services to high-mobility users, one of the promising solution prop...Recent years have witnessed a huge demand for ubiquitous communications services from continuously moving users. In order to provide seamless network services to high-mobility users, one of the promising solution proposed by 3 GPP is the deployment of moving-relays. In this article, we introduce the concept of Moving-Personal-Cell(mPC), which is a type of moving-relays. mPC is a user-centric network, which aims to provide reliable network services to moving users. A mPC receives data-traffic from eNB and its neighboring mPCs via wireless backhaul and sidehual links respectively and forwards the received data to its serving users. In addition to this, mPC can also increase the network capacity by caching and distributing the popular contents to its serving users. Besides these pros, the mPC also has some limitations, as its performance is highly affected by cross-tier and co-tier interferences. In this article, we analyze the effect of these interferences on mPCs performance. Our results show that the performance of mPC network is equally affected by the capacity of wireless backhaul, sidehaul, and access links. Moreover, since mPCs accommodate data traffic from wireless backhaul, sidehaul links, and content cache, their performance is also affected by the ratio of data-traffic delivered via these links.展开更多
Both ultra-reliable low latency and high-data-rate communications are required by connective vehicles. Millimeter wave(mm Wave) with large bandwidth is a key technology to support high-data-rate communications. In thi...Both ultra-reliable low latency and high-data-rate communications are required by connective vehicles. Millimeter wave(mm Wave) with large bandwidth is a key technology to support high-data-rate communications. In this paper, the 28 GHz wideband vehicle-to-infrastructure channel is characterized for the urban environment in a major street in Manhattan. The deployment of the transmitter and the receiver, as well as the traffic models, are selected by considering the recommendation by 3GPP TR 37.885. Ray tracing simulator with calibrated electromagnetic parameters is employed in this work to practically conduct intensive simulations. The 3D environment model is reconstructed from OpenStreetMap. The power delay profile, path loss, root-meansquare delay spread, K-factor and so on, are extracted from the calibrated simulation results. The evolution of the parameters, as well as their statistical properties, are analyzed and modeled. The work of this paper helps the researchers understand the propagation channel for designing mmWave technologies and communication system in a similar scenario.展开更多
基金supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(2020R1I1A3054824)supported by the Basic Research Program through the National Research Foundation of Korea(NRF)funded by the MSIT(2021R1A4A1032762)+1 种基金supported under the framework of international cooperation program managed by the National Research Foundation of Korea(2019K2A9A1A06091737)supported by the Technology Development Program to Solve Climate Changes of the Korean NRF(2021M1A2A2061335).
文摘Flexible hydrogels are receiving significant attention for their application in wearable sensors.However,most hydrogel materials exhibit weak and one-time adhesion,low sensitivity,ice crystallization,water evaporation,and poor self-recovery,thereby limiting their application as sensors.These issues are only partly addressed in previous studies.Herein,a multiplecrosslinked poly(2-(methacryloyloxy)ethyl)dimethyl-(3-sulfopropyl)ammonium hydroxide-co-acrylamide)(P(SBMA-co-AAm))multifunctional hydrogel is prepared via a one-pot synthesis method to overcome the aforementioned limitations.Specifically,ions,glycerol,and 2-(methacryloyloxy)ethyl)dimethyl-(3-sulfopropyl)ammonium hydroxide are incorporated to reduce the freezing point and improve the moisture retention ability.The proposed hydrogel is superior to existing hydrogels because it exhibits good stretchability(a strain of 2900%),self-healing properties,and transparency through effective energy dissipation in its dynamic crosslinked network.Further,2-(methacryloyloxy)ethyl)dimethyl-(3-sulfopropyl)ammonium hydroxide as a zwitterion monomer results in an excellent gauge factor of 43.4 at strains of 1300-1600%by improving the ion transportability and achieving a strong adhesion of 20.9 kPa owing to the dipole-dipole moment.The proposed hydrogel is promising for next-generation biomedical applications,such as soft robots,and health monitoring.
基金supported by Institute for Information and communications Technology Promotion(IITP)grant funded by the Korea government(MSIP)(No.R0101-15-244,Development of 5G Mobile Communication Technologies for Hyperconnected smart services)
文摘Recent years have witnessed a huge demand for ubiquitous communications services from continuously moving users. In order to provide seamless network services to high-mobility users, one of the promising solution proposed by 3 GPP is the deployment of moving-relays. In this article, we introduce the concept of Moving-Personal-Cell(mPC), which is a type of moving-relays. mPC is a user-centric network, which aims to provide reliable network services to moving users. A mPC receives data-traffic from eNB and its neighboring mPCs via wireless backhaul and sidehual links respectively and forwards the received data to its serving users. In addition to this, mPC can also increase the network capacity by caching and distributing the popular contents to its serving users. Besides these pros, the mPC also has some limitations, as its performance is highly affected by cross-tier and co-tier interferences. In this article, we analyze the effect of these interferences on mPCs performance. Our results show that the performance of mPC network is equally affected by the capacity of wireless backhaul, sidehaul, and access links. Moreover, since mPCs accommodate data traffic from wireless backhaul, sidehaul links, and content cache, their performance is also affected by the ratio of data-traffic delivered via these links.
基金supported by Institute for Information & communications Technology Promotion(IITP) grant funded by the Korea government(MSIT) (No. 2018-0-00792, QoE improvement of open Wi-Fi on public transportation for the reduction of communication expense)
文摘Both ultra-reliable low latency and high-data-rate communications are required by connective vehicles. Millimeter wave(mm Wave) with large bandwidth is a key technology to support high-data-rate communications. In this paper, the 28 GHz wideband vehicle-to-infrastructure channel is characterized for the urban environment in a major street in Manhattan. The deployment of the transmitter and the receiver, as well as the traffic models, are selected by considering the recommendation by 3GPP TR 37.885. Ray tracing simulator with calibrated electromagnetic parameters is employed in this work to practically conduct intensive simulations. The 3D environment model is reconstructed from OpenStreetMap. The power delay profile, path loss, root-meansquare delay spread, K-factor and so on, are extracted from the calibrated simulation results. The evolution of the parameters, as well as their statistical properties, are analyzed and modeled. The work of this paper helps the researchers understand the propagation channel for designing mmWave technologies and communication system in a similar scenario.
